Nonhormonal Male Contraceptive Development-Strategies for Progress.

Despite the widely demonstrated public health benefits of contraception, limited contraceptive options are available for men, placing both the contraceptive burden and opportunity solely on women. This review outlines the need for an increased focus on male contraceptive development and highlights several related topics, including the perspectives of women and men on male contraceptives, historical challenges, and reasons behind the persistent delays in male contraceptive development. It also discusses the importance of serendipitous observations in drug discovery and the limitations of depleting sperm or spermatogenic cells as a contraceptive approach. It further provides an overview of ongoing research and development on novel methods, with a goal to offer insights into the multifaceted aspects of nonhormonal male contraceptive development, addressing its implications for the health of men and women. SIGNIFICANCE STATEMENT: Despite well over half a century of effort in developing male contraceptives, there are no approved male contraceptive drugs on the market. This review aims to present strategies for progress in nonhormonal male contraception based on lessons learned from history, with the hope of expediting development and bringing a male contraceptive drug closer to reality.

Male contraception is coming: Who do men want to prescribe their birth control?

OBJECTIVE: To assess men's preferences for healthcare provider from whom they would obtain hormonal male contraceptive (HMC) methods. STUDY DESIGN: We asked participants from 3 clinical trials of investigational HMC methods-an oral pill (11ß-Methyl-19-nortestosterone-17ß-dodecylcarbonate, 11ß-MNTDC), intramuscular or subcutaneous injection (Dimethandrolone undecanoate), and transdermal gel (Nestorone and testosterone)-to rank their top 3 preferred HMC providers from a list including: men's health doctor (urologist/andrologist), hormonal doctor (endocrinologist), reproductive health doctor (OB/GYN), family planning clinician (community health worker, midwife, nurse practitioner), regular doctor (family medicine/internal medicine), and community pharmacist. We examined preferences based on their rankings and conducted bivariate analyses. Collapsing the various specialists (men's health doctor, hormonal doctor, reproductive health doctor, and family planning clinician) into a single provider type, we examined participant demographics against provider preference (regular doctor, pharmacist, or specialist). RESULTS: Participants across the 3 trials (n = 124) ranked their regular doctor (44%) and community pharmacist (18%) as their most preferred HMC provider; these preferences did not differ significantly by trial and drug formulation. Specialists in family planning (13%), men's health (12%), reproductive health (10%), and hormones (4%) were least frequently ranked as their preferred provider. Older and higher educated participants more often preferred specialists over regular doctors and pharmacists (p = 0.02 and p = 0.01). CONCLUSIONS: Despite receiving contraceptive steroid hormones and care from endocrinologists and family planning specialists in a clinical trial, participants would prefer to obtain contraception from their regular doctor. IMPLICATIONS: As most men expect to obtain hormonal male contraceptives from their regular doctor when commercially available, primary care physicians should become familiar with HMCs and be prepared to provide counseling and options accordingly.

Androgens in male contraception.

Rates of unplanned pregnancies are high globally, burdening women and families. Efforts to develop male contraceptive agents have been thwarted by unacceptable failure rates, side effects and a dearth of pharmaceutical industry involvement. Hormonal male contraception consists of exogenous androgens which exert negative feedback on the hypothalamic-pituitary-gonadal axis and suppress gonadotropin production. This in turn suppresses testicular testosterone production and sperm maturation. Addition of a progestin suppresses spermatogenesis more effectively in men. Contraceptive efficacy studies in couples have shown male hormonal methods are effective and reversible, but also may come with side effects related to sexual desire, acne and serum cholesterol and inconvenient methods of dosing and delivery. Recently, novel androgens as potential contraceptive agents are being evaluated in early clinical trials and look to overcome these drawbacks. Here we summarize landmark studies of prototype male hormonal contraceptives, showcasing recent advances and future prospects in this important area of public health.

Vasectomy and vasectomy reversal: a comprehensive approach to the evolving spectrum of care.

Male reproduction and male contraception form an important spectrum within men's health. In this issue's Views and Reviews, four author groups detail important new developments in vasectomy clinical practice guidelines, emerging and investigational techniques in the fields of hormonal and nonhormonal male contraception, useful paradigms for patient care when deciding between sperm extraction with in vitro fertilization and vasectomy reversal, and finally, a state-of-the-art overview of recent developments in vasectomy reversal microsurgery. These articles will provide readers with a contemporary understanding of the rapidly evolving spectrum of male reproductive and contraceptive health care.

Young Adult Males' Perspectives of Male Hormonal Contraception.

OBJECTIVE: To evaluate the willingness of young adult males to use male hormonal contraception and to determine the most desirable formulation. METHODS: An institutional review board-approved survey measuring the willingness to use MHC was dispersed to two distinct populations: University of Cincinnati postgraduate programs and Cincinnati Health Department clinics. Questions on the survey allowed for the collection of demographic characteristics, as well as the preferred method of MHC, and concerns regarding potential adverse effects. This survey was directed at young adult males; therefore, only male participants who were 18 to 35 years old were included for analysis. Results were reported as frequencies in each group and χ2 analyses were performed to compare groups, with a P < 0.05 considered significant. RESULTS: Of 162 total survey participants, 45% would use MHC, whereas 30.9% were unsure and 23.5% would not use MHC. Overall, the University of Cincinnati survey population was more likely to be interested in using MHC than the Cincinnati Health Department population (P < 0.05). In both populations, most were interested in using the injectable form. Cited concerns deterring participants from using MHC were different between these two populations, with University of Cincinnati participants more frequently expressing concerns about possible failure of the contraceptive method, whereas Cincinnati Health Department participants had concerns about potential adverse effects (P < 0.001). CONCLUSIONS: There is significant interest among young adult males in using various forms of MHC, especially in injectable form. Differences in views of MHC were seen in two distinct male populations. Specifically, males who achieved a higher level of education, were employed, or in a relationship were found to more frequently be willing to use MHC. With further research and funding, MHC may serve as a significant way to decrease unintended pregnancies in the future.

Update on Novel Hormonal and Nonhormonal Male Contraceptive Development.

BACKGROUND: The advent of new methods of male contraception would increase contraceptive options for men and women and advance male contraceptive agency. Pharmaceutical R&D for male contraception has been dormant since the 1990s. The Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) has supported a contraceptive development program since 1969 and supports most ongoing hormonal male contraceptive development. Nonhormonal methods are in earlier stages of development. CONTENT: Several hormonal male contraceptive agents have entered clinical trials. Novel single agent products being evaluated include dimethandrolone undecanoate, 11ß-methyl-nortestosterone dodecylcarbonate, and 7α-methyl-19-nortestosterone. A contraceptive efficacy trial of Nestorone®/testosterone gel is underway. Potential nonhormonal methods are at preclinical stages of development. Many nonhormonal male contraceptive targets that affect sperm production, sperm function, or sperm transport have been identified. SUMMARY: NICHD supports development of reversible male contraceptive agents. Other organizations such as the World Health Organization, the Population Council, and the Male Contraception Initiative are pursuing male contraceptive development, but industry involvement remains limited.

Fertility desire concordance and contraceptive use among couples living with HIV in northern Nigeria.

OBJECTIVES: We aimed to determine the concordance between own and perceived partner fertility intentions and identify predictors of contraceptive use among couples receiving antiretroviral therapy in Kano, Nigeria. METHODS: A structured, validated questionnaire was used to interview 399 married men and women receiving antiretroviral therapy. Adjusted odds ratios for predictors of contraceptive use were derived from multivariate logistic regression models. RESULTS: Most couples (68.9%) had concordant fertility intentions. Only 10.0% of couples had discordant fertility intentions. Among 232 couples (58.1%) at least one partner used contraception. Male condoms were used by 45.9% of couples (n = 183). Female methods were used by 175 couples (43.9%). Contraceptive use was significantly higher in participants who were older (≥30 years), better educated (secondary or post-secondary), had a higher monthly income (NGN ≥30,000), longer marriage duration (≥5 years), at least one living child, >1 year of antiretroviral treatment, and who were living with a serodiscordant partner and in circumstances where the decision on contraception was made by the female partner or jointly by both partners (all p < 0.05). Contraceptive use was significantly lower in participants who had not been sexually active in the last 6 months, where both partners wanted more children, and in situations lacking spousal communication about family planning (all p < 0.05). CONCLUSION: One in 10 couples had discordant fertility intentions. Contraceptive use was suboptimal and was predicted by age, education, income, length of marriage, number of children, duration of antiretroviral therapy, partner's serostatus, sexual activity, fertility intention, spousal communication and the contraceptive decision-maker. Our findings highlight the need for spousal communication, joint contraceptive decision making and the integration of reproductive health services with antiretroviral therapy services.

Assessing safety in hormonal male contraception: a critical appraisal of adverse events reported in a male contraceptive trial.

INTRODUCTION: There is unmet need for male contraceptive options, but a recent injectable combination male contraceptive trial was terminated early due to adverse events (AEs). METHODS: We examined the frequency of reported AEs by male research participants compared with AEs reported in prescribing information of approved female hormonal contraceptive methods. Published data from trials of the top five most-used female hormonal contraceptives, supplemented by contemporary contraceptive research, were compared with the frequency of AEs reported in a male injectable hormonal contraceptive trial. RESULTS: We observed similar frequencies of AEs reported by users of male contraceptives compared with those reported by female users. Among quantitatively comparable AEs, compared with men, women reported experiencing higher frequencies of headaches, pelvic pain, and weight gain and similar frequencies of decreased libido. Compared with women, men reported experiencing higher frequencies of acne and mood changes. Men discontinued participation due to AEs at a lower frequency than women. CONCLUSIONS: Female hormonal methods generally have similar frequencies of AEs to those reported in a recent male hormonal contraceptive trial, and male users had lower rates of discontinuation due to AEs. There were fewer serious AEs of the male contraceptive than reported in contemporary female trials which resulted in FDA licensure. This suggests there may be implicit bias in the scientific community regarding the level of acceptable risk for users of male contraceptive methods.

Male Participation in Reproductive Health Interventions in Sub-Saharan Africa: A Scoping Review.

CONTEXT: Despite improvements in reproductive health indicators among women living in Sub-Saharan Africa, the persistence of poor outcomes underscores the need to examine recent interventions to inform future research, programming and policy. Because men in this context have an outsize role in reproductive decision making, assessing their involvement in reproductive health programs is an important step in meeting men's needs, supporting women's health and improving family health. METHODS: A scoping review was conducted to identify relevant literature and assess evidence of the impact of male involvement in reproductive health interventions. Seven databases were searched using terms related to male involvement and reproductive health; searches were limited to research conducted in Sub-Saharan Africa and published in English between 2007 and 2018. Remaining studies were assessed by participant characteristics, settings, research design, theoretical frameworks, outcome measures and findings. RESULTS: Searches identified 18 studies conducted in eight countries. Interventions engaged participants by using such strategies as community health workers, written invitation, peers, community or religious leaders and media campaigns. Results show that men are willing to participate in reproductive health programs and that their involvement is associated with increased uptake of family planning services, and HIV counseling and testing; reduction in risk behaviors; and improved maternal health and spousal communication. CONCLUSIONS: Given the findings that male involvement is positively associated with improved reproductive health outcomes in Sub-Saharan Africa, health providers and program planners should consider including men in reproductive health interventions, when feasible.

RESUMEN Contexto: A pesar de las mejoras observadas en los indicadores de salud reproductiva en las mujeres que viven en África subsahariana, la persistencia de malos resultados subraya la necesidad de examinar intervenciones recientes para sustentar futuras investigaciones, programas y políticas. Debido a que los hombres en este contexto tienen un papel enorme en la toma de decisiones reproductivas, evaluar su participación en los programas de salud reproductiva es un paso importante para responder a las necesidades de los hombres, apoyar la salud de las mujeres y mejorar la salud familiar. Métodos: Se realizó una revisión de alcance para identificar bibliografía relevante y evaluar la evidencia del impacto de la participación masculina en las intervenciones de salud reproductiva. Se realizaron búsquedas en siete bases de datos utilizando términos relacionados con la participación masculina y la salud reproductiva; las búsquedas se limitaron a investigaciones realizadas en África subsahariana y que fueron publicadas en inglés entre 2007 y 2018. Los estudios restantes se evaluaron según las características de los participantes, los entornos, el diseño de la investigación, los marcos teóricos, las medidas de resultado y los hallazgos. Resultados: Las búsquedas identificaron 18 estudios conducidos en ocho países. Las intervenciones involucraron a los participantes mediante estrategias tales como la labor de trabajadores de salud comunitarios, invitaciones por escrito, interacción con pares, líderes comunitarios o religiosos y campañas en los medios. Los resultados muestran que los hombres están dispuestos a participar en programas de salud reproductiva y que su participación está asociada con una mayor aceptación de los servicios de planificación familiar, así como de consejería y pruebas de VIH, reducción de comportamientos de riesgo, y mejor salud materna y comunicación conyugal. Conclusiones: Con base en los hallazgos que indican que la participación masculina se asocia positivamente con mejores resultados de salud reproductiva en el África subsahariana, los proveedores de servicios de salud y los planificadores de programas deberían considerar incluir a los hombres en las intervenciones de salud reproductiva cuando sea posible.

RÉSUMÉ Contexte: Malgré l'amélioration des indicateurs de santé reproductive chez les femmes d'Afrique subsaharienne, la persistance de résultats défavorables souligne la nécessité d'examiner les interventions récentes en vue d'éclairer la recherche, la programmation et les politiques futures. Étant donné, dans ce contexte, l'immense rôle des hommes dans les décisions ayant trait à la reproduction, l'évaluation de leur participation aux programmes de santé reproductive représente une étape importante en termes de réponse aux besoins des hommes, de soutien de la santé des femmes et d'amélioration de la santé des familles. Méthodes: Un examen de portée a été effectué pour identifier la littérature pertinente et évaluer les signes de l'impact de la participation masculine aux interventions de santé reproductive. La recherche a été menée dans sept bases de données au moyen de termes associés à la participation masculine et à la santé reproductive; elle s'est limitée aux études effectuées en Afrique subsaharienne et publiées en anglais entre 2007 et 2018. Les études restantes ont été évaluées d'après les caractéristiques des participants, les contextes, le plan de recherche, les cadres théoriques, les mesures de résultat et les observations. Résultats: La recherche a identifé 18 études menées dans huit pays. Les interventions engageaient les participants au moyen de stratégies recourant, notamment, aux agents de santé communautaire, aux invitations écrites, aux pairs, aux dirigeants communautaires ou religieux et aux campagnes médiatiques. Les résultats montrent que les hommes sont disposés à participer aux programmes de santé reproductive et que leur participation est associée à une adoption accrue des services de planification familiale et du conseil et dépistage du VIH, à la réduction des comportements à risques et à l'amélioration de la santé maternelle et de la communication au sein du couple. Conclusions: Face au constat de l'association positive entre la participation masculine et l'amélioration des résultats de santé reproductive en Afrique subsaharienne, il convient que les prestataires de santé et les planificateurs de programmes incluent si possible les hommes dans les interventions de santé reproductive.

Field-testing a single-dose immunocontraceptive in free-ranging male capybara (Hydrochoerus hydrochaeris): Evaluation of effects on reproductive physiology, secondary sexual characteristics, and agonistic behavior.

Controlling wildlife populations to mitigate human-wildlife conflicts and the spread of zoonotic diseases is an ever-growing necessity. The objective of this study was to evaluate a single-dose anti-gonadotropin-releasing hormone vaccine (GonaCon, USDA/NWRC, Fort Collins, CO, USA) as a non-lethal alternative for population control in free-ranging, synanthropic male capybara. In addition to infertility efficacy of this treatment, potential effects on the alpha male's secondary sexual characteristics and agonist behavior need to be assessed because any alterations in these factors could lead to population management failure. The treatment group (n = 3) received 1 mL of the anti-GnRH vaccine, intramuscularly, and the control group (n = 2) a 1 mL sham vaccine. Reproductive behavior and social group dynamics were monitored for 30 days prior to inoculation (June 2017) with continuous observations occurring during the study period. Antifertility effects were assessed by conducting exams of testicular morphology, semen characteristics, and histological analysis (after 270 days via hemi-gonadectomy). Compared to the control group, the testicles of the treated males had severe atrophy (P <  0.05), oligozoospermia and greater numbers of sperm cells in a static developmental phase. Courtship and agonistic alpha male behavior were not altered, and the group's social integrity was maintained. Results indicate there was 100% infertility in capybara males, observed throughout the study period of 18 months, and equally important, the male's alpha characteristics were not affected by the treatment, which is imperative for successful capybara population control efforts.

Identifying determinants of Mozambican men's willingness to use a male contraceptive pill.

Objective: Given the possibility of a male contraceptive pill in the near future, understanding men's attitudes towards this contraceptive method is crucial, especially in high-risk populations with limited access to education. This research was conducted to identify the determinants of Mozambican men's willingness to use a contraceptive pill when it is made available. Methods: A sample of 412 Mozambican men was presented with 36 vignettes comprising four within-subject factors (cost of pills, pill efficacy, side effects and context). Each vignette presented a scenario in which a man is asked by his partner to use the contraceptive pill, and participants indicated their own willingness to use the pill under each circumstance. Results: Cluster analysis revealed that participants took one of four different positions regarding their willingness to use a contraceptive pill: never (11%); depends on side effects alone (25%); depends on side effects and costs (11%); depends on side effects and context (46%). These positions were associated with participants' sociodemographic characteristics. Conclusion: Among the Mozambican men in this study, a minority appeared to believe that the responsibility for contraception should be shared between sexual partners. Men's willingness to use a contraceptive pill was, however, more pronounced in the case of serious medical risk to their partner. Overall, only about one-fifth of participants were either reluctant or unwilling to consider using a male contraceptive pill.

Would male hormonal contraceptives affect cardiovascular risk?

The aim of hormonal male contraception is to prevent unintended pregnancies by suppressing spermatogenesis. Hormonal male contraception is based on the principle that exogenous administration of androgens and other hormones such as progestins suppress circulating gonadotropin concentrations, decreasing testicular Leydig cell and Sertoli cell activity and spermatogenesis. In order to achieve more complete suppression of circulating gonadotropins and spermatogenesis, a progestin has been added testosterone to the most recent efficacy trials of hormonal male contraceptives. This review focusses on the potential effects of male hormonal contraceptives on cardiovascular risk factors, lipids and body composition, mainly in the target group of younger to middle-aged men. Present data suggest that hormonal male contraception can be reasonably regarded as safe in terms of cardiovascular risk. However, as all trials have been relatively short (< 3 years), a final statement regarding the cardiovascular safety of hormonal male contraception, especially in long-term use, cannot be made. Older men with at high risk of cardiovascular event might not be good candidates for hormonal male contraception. The potential adverse effects of hormonal contraceptives on cardiovascular risk appear to depend greatly on the choice of the progestin in regimens for hormonal male contraceptives. In the development of prospective hormonal male contraception, data on longer-term cardiovascular safety will be essential.

[Male hormonal contraception: past, present, future]. / Férfi hormonális fogamzásgátlás: múlt, jelen, jövo.

In certain regions of the world the enormous rate of population growth raises economic and public health concerns and widely accessible contraceptive methods would be desired. In contrast, in other countries the use of effective contraception is a question of individual preferences. Today, most of the reliable contraceptive methods are applied by women, while the options for male methods are quite limited. It is well known that significant portion of pregnancies are still unplanned and several data revealed men's willingness to take part in family planning. Based on these needs, remarkable efforts have been made to develop a suitable hormonal contraceptive agent for men. With the exogenous suppression of follicle stimulating hormone and luteinizing hormone secretion, the inhibition of the testicular testosterone production and the spermatogenesis can be achieved. In the beginning, testosterone-derivatives, or testosterone-progestin combinations were administered, later synthetic androgen agents were developed. Despite of these efforts, unfortunately, there is no safe, widely feasible male hormonal contraception to date, but in the future this goal can be achieved by solving the key hurdles. Orv Hetil. 2017; 158(46): 1819-1830.

Male hormonal contraception: hope and promise.

Family planning is a shared responsibility, but available male-directed contraceptive methods are either not easily reversible (vasectomy) or not sufficiently effective (condom). However, roughly 20% of couples using a contraceptive method worldwide, and up to 80% in some countries, still choose a male-directed method. Male hormonal contraception is highly effective, with perfect use failure rates of 0·6% (95% CI 0·3-1·1) if sperm concentrations of less than 1 million per mL are maintained. After cessation of male hormonal contraception, sperm output fully recovers in a predictable manner, resulting in pregnancies and livebirths. Spontaneous miscarriage and fetal malformation rates after recovery of sperm output overlap those in the general population. Short-term adverse events-acne, night sweats, increased weight, and altered mood and libido-are recognised, but are generally mild. Further optimisation of specific androgen-progestin regimens and phase 3 studies of lead combinations are still needed to successfully develop an approved male hormonal contraceptive and to identify long-term side-effects.

The Development of In Vivo Measures to Assess the Impact of Sex-Drive Reducing Medications in an Offender with an Intellectual Disability.

The ability to adequately evaluate medications in the treatment of paraphilias has been limited by reliance upon self-report as a measure of effectiveness over periods of time that may be too short to detect reoffending. One solution to this shortcoming is the development of valid, long-term, stable assessment measures. The purpose of this case study was to analyze the effects of Prozac and Provera on an array of behaviors germane to the successful treatment of paraphilias, including: (a) sexual arousal in the laboratory and natural environment, (b) sexual thoughts (deviant and nondeviant) accompanied by arousal in the natural environment, and (c) overt actions in the community associated with increased risk of reoffending over a 31-month period for an exhibitionist with an intellectual disability. Despite the ineffectiveness of the medications, the measures demonstrated long-term, differentiated significant clinical responding; further underscored the importance of assessing deviant sexual arousal and adherence to relapse-prevention procedures in the natural environment; and provided a new methodology to assess sexual preoccupations and sexual arousal. Use of these in vivo measures raises questions regarding their potential to improve the predictability of risk assessments, and serve as an aide in the analysis of whether a treatment procedure is effective for an individual.

Non-hormonal male contraception: A review and development of an Eppin based contraceptive.

Developing a non-hormonal male contraceptive requires identifying and characterizing an appropriate target and demonstrating its essential role in reproduction. Here we review the development of male contraceptive targets and the current therapeutic agents under consideration. In addition, the development of EPPIN as a target for contraception is reviewed. EPPIN is a well characterized surface protein on human spermatozoa that has an essential function in primate reproduction. EPPIN is discussed as an example of target development, testing in non-human primates, and the search for small organic compounds that mimic contraceptive antibodies; binding EPPIN and blocking sperm motility. Although many hurdles remain before the success of a non-hormonal male contraceptive, continued persistence should yield a marketable product.

Valproic Acid Enhances the Anti-tumor Effect of (-)-gossypol to Burkitt Lymphoma Namalwa Cells.

Burkitt lymphoma is a highly aggressive B-cell neoplasm. New therapeutic methods are needed to overcome the adverse effect of intensive chemotherapy regimens. Valproic acid and (-)-gossypol are two kinds of chemical compounds used as new anti-tumor drugs in recent years. To investigate the anti-tumor effect of valproic acid and (-)-gossypol, Burkitt lymphoma Namalwa cells were cultured and treated with valproic acid and (-)-gossypol at different concentrations. The proliferation of Namalwa cells was dramatically suppressed after the combination treatment with 2 mmol/L valproic acid and 5 µmol/L (-)-gossypol. The combined treatment also enhanced intrinsic apoptosis by down-regulating anti-apoptotic protein Mcl-1. Moreover, the autophagy flux significantly increased in Namalwa cells after combined treatment. However, the enhanced autophagy showed little effect on cell survival with present regimen. The results confirmed that combination of valproic acid and (-)-gossypol had synergistic anti-tumor effect to Burkitt lymphoma Namalwa cells. The related mechanisms might include the down-regulation of anti-apoptotic protein Mcl-1 and avianized pro-survival role of autophagy.

Importance of male fertility control in family planning.

The world population, currently estimated to be almost seven billion, is expected to double in less than four decades. The projected population growth will cause severe competition for existing resources, not to mention the issue of overcrowding of the planet and additional greenhouse gases that will have an adverse effect on the ecological health of the planet. A recent survey conducted by the United Nations Population Control Division shows that the majority of today's young men in many countries are willing to participate in family planning by taking full control of their fertility, an important global health issue. However, the contraceptive needs of tens of millions of men/couples go unmet every single day and results in millions of unwanted pregnancies. Ever since the approval of the birth control pill by the Food and Drug Administration (FDA) in 1960, scientists have been hoping for a male equivalent. It has, however, been a difficult road, in part because of the complicated science of the male reproductive system. It is easier to control a monthly event of ovulation in women than to regulate the production of millions of fertile spermatozoa every day in men. Thus, the contraceptive options for men have not changed in decades and are still limited to the use of condoms, a timely withdrawal/pulling out (coitus interruptus) or vasectomy, a minor surgical procedure in which the vas deferens is occluded to prevent the release of spermatozoa during ejaculation. The first two approaches have a relatively higher failure rate, whereas the last approach is largely irreversible and not suitable for younger men. In this article, we will discuss various approaches currently available for men to take control of their fertility. Our intention is to discuss the details of three similar approaches that will provide safe, affordable and reversible contraception for men and are close to being approved for use by millions of men around the globe. The availability of safe, reversible and reliable male contraceptives will allow men and women to take full control of their fertility in family planning.

Injection of a chemical castration agent, zinc gluconate, into the testes of cats results in the impairment of spermatogenesis: a potentially irreversible contraceptive approach for this species?

Male sterilization by chemical agents is a nonsurgical contraceptive approach designed to induce azoospermia and, therefore, infertility. Intratesticular injection of zinc gluconate for sterilization of dogs has been described, but its use in cats remains limited. The objective of the present study was to evaluate, by light and transmission electron microscopy, the efficacy of a single intratesticular injection of a zinc gluconate solution (Testoblock) as a sterilant for male cats. Twelve sexually mature mixed breed cats were allocated at random into two groups (control = 6; treated = 6) and given a single injection into each testis of either isotonic saline or zinc gluconate, respectively. Histopathologic and ultrastructural evaluation was assessed at 120 days postinjection. Histopathologic changes were not detected in the testes from the control group. However, histologic evaluation of the treated group revealed atrophic and dilated seminiferous tubules, a decrease in the number of germ cells, and incomplete spermatogenesis. Sertoli cells had various degrees of cytoplasmic vacuolization. Intertubular tissue revealed active fibroblasts, collagen deposition, and inflammatory cells. The diameter of seminiferous tubules, epithelial height and tubular area were reduced (P < 0.05) in the treated group compared with controls. Azoospermia occurred in 8 of the 11 treated cats (73%). Ultrastructural evaluation of Leydig cells revealed loss of nuclear chromatin, increased smooth endoplasmatic reticulum, and mitochondria degeneration. Intratesticular injection of zinc gluconate solution impaired spermatogenesis in cats and has great potential as a permanent sterilant in this species.