Donor sibling relations among adult offspring conceived via insemination by lesbian parents.

STUDY QUESTION: How do adult offspring in planned lesbian-parent families feel about and relate to their donor (half) sibling(s) (DS)? SUMMARY ANSWER: A majority of offspring had found DS and maintained good ongoing relationships, and all offspring (regardless of whether a DS had been identified) were satisfied with their knowledge of and contact level with the DS. WHAT IS KNOWN ALREADY: The first generation of donor insemination offspring of intended lesbian-parent families is now in their 30s. Coincident with this is an increased use of DNA testing and genetic ancestry websites, facilitating the discovery of donor siblings from a common sperm donor. Few studies of offspring and their DS include sexual minority parent (SMP) families, and only sparse data separately analyze the offspring of SMP families or extend the analyses to established adult offspring. STUDY DESIGN, SIZE, DURATION: This cohort study included 75 adult offspring, longitudinally followed since conception in lesbian-parent families. Quantitative analyses were performed from online surveys of the offspring in the seventh wave of the 36-year study, with a 90% family retention rate. The data were collected from March 2021 to November 2022. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants were 30- to 33-year-old donor insemination offspring whose lesbian parents enrolled in a US prospective longitudinal study when these offspring were conceived. Offspring who knew of a DS were asked about their numbers found, characteristics or motivations for meeting, DS terminology, relationship quality and maintenance, and impact of the DS contact on others. All offspring (with or without known DS) were asked about the importance of knowing if they have DS and their terminology, satisfaction with information about DS, and feelings about future contact. MAIN RESULTS AND THE ROLE OF CHANCE: Of offspring, 53% (n = 40) had found DS in modest numbers, via a DS or sperm bank registry in 45% of cases, and most of these offspring had made contact. The offspring had their meeting motivations fulfilled, viewed the DS as acquaintances more often than siblings or friends, and maintained good relationships via meetings, social media, and cell phone communication. They disclosed their DS meetings to most relatives with neutral impact. The offspring, whether with known or unknown DS, felt neutral about the importance of knowing if they had DS, were satisfied with what they knew (or did not know) of the DS, and were satisfied with their current level of DS contact. This study is the largest, longest-running longitudinal study of intended lesbian-parent families and their offspring, and due to its prospective nature, is not biased by over-sampling offspring who were already satisfied with their DS. LIMITATIONS, REASONS FOR CAUTION: The sample was from the USA, and mostly White, highly educated individuals, not representative of the diversity of donor insemination offspring of lesbian-parent families. WIDER IMPLICATIONS OF THE FINDINGS: While about half of the offspring found out about DS, the other half did not. Regardless of knowing of a DS, these adult offspring of lesbian parents were satisfied with their level of DS contact. Early disclosure and identity formation about being donor-conceived in a lesbian-parent family may distinguish these study participants from donor insemination offspring and adoptees in the general population, who may be more compelled to seek genetic relatives. The study participants who sought DS mostly found a modest number of them, in contrast to reports in studies that have found large numbers of DS. This may be because one-third of study offspring had donors known to the families since conception, who may have been less likely to participate in commercial sperm banking or internet donation sites, where quotas are difficult to enforce or nonexistent. The study results have implications for anyone considering gamete donation, gamete donors, donor-conceived offspring, and/or gamete banks, as well as the medical and public policy professionals who advise them. STUDY FUNDING/COMPETING INTEREST(S): No funding was provided for this project. The authors have no competing interests. TRIAL REGISTRATION NUMBER: N/A.

On the Donation of Eggs, Sperm, and Selves.

Every single human being who has ever been conceived has come into existence precisely because God wants him or her to exist. The present article offers psychological and spiritual considerations to assist people who, in a variety of settings, are evaluating medical-assisted technologies that require the removal of gametes from the body, especially those procedures that involve the buying and selling of gametes. Gamete "donation" is a misnomer when the transactions involve cash payment. Gamete "donation" is contrasted with the "self-donation" that a married couple makes to each other, and by extension to their children, in the marital embrace. The article draws out some of the implications of this contrast, particularly to the child's sense of identity. Particular attention is drawn to the mistakes and mix-ups that can occur when the gametes are removed from the body, which would be literally impossible under the circumstances of natural procreation. I conclude that the perennial teaching of the Catholic Church makes a uniquely humane and personalist contribution to the important public conversation about the use of assisted reproduction.

The Nature of the Shared Environment.

While a standard part of twin modeling, the magnitude of shared environment (c2) is rarely examined by comparing estimates obtained using other methods. To clarify these effects on familial resemblance, we estimated c2 for 20 diverse phenotypes in: (i) monozygotic and dizygotic twins, (ii) all step-siblings, and (iii) reared together and apart half-siblings, ascertained from the Swedish general population. The mean c2 estimates (± 95% CIs) differed across methods and were higher from twins (0.18; 0.13-0.23) than from the step (0.12; 0.09-0.14) and half-sibs (0.09; 0.06-0.13). c2 estimates correlated moderately across these three methods (ICC = + 0.28). When step-siblings from blended (each sib biologically related to one parent) and adoption-like families (one sib offspring of both parents and one of neither), were examined separately, resemblance was much lower in the latter. We need to clarify the range of environmental processes now considered together under the term "shared environment."

A Bivariate Genetic Analysis of Drug Abuse Ascertained Through Medical and Criminal Registries in Swedish Twins, Siblings and Half-Siblings.

Using Swedish nationwide registry data, the authors investigated the correlation of genetic and environmental risk factors in the etiology of drug abuse as ascertained from medical and criminal registries by modeling twin and sibling data. Medical drug abuse was defined using public inpatient and outpatient records, while criminal drug abuse was ascertained through legal records. Twin, full and half sibling pairs were obtained from the national twin and genealogical registers. Information about sibling pair residence within the same household was obtained from Statistics Sweden. Standard bivariate genetic structural equation modeling was applied to the population-based data on drug abuse ascertained through medical and crime registries, using OpenMx. Analyses of all possible pairs of twins (MZ: N = 4482; DZ: N = 9838 pairs), full- (N = 1,278,086) and half-siblings (paternal: N = 7767; maternal N = 70,553) who grew up together suggested that factors explaining familial resemblance for drug abuse as defined through medical or criminal registries were mostly the same. Results showed substantial heritability and moderate contributions of shared environmental factors to drug abuse; both were higher in males versus females, and higher for drug abuse ascertained through criminal than medical records. Because of the low prevalence of both assessments of drug abuse, having access to population data was crucial to obtain stable estimates. Using objective registry data, the authors found that drug abuse-whether ascertained through medical versus criminal records-was highly heritable. Furthermore, shared environmental factors contributed significantly to the liability of drug abuse. Genetic and shared environmental risk factors for these two forms of drug abuse were highly correlated.

The etiologic role of genetic and environmental factors in criminal behavior as determined from full- and half-sibling pairs: an evaluation of the validity of the twin method.

BACKGROUND: Twin studies have shown that criminal behavior (CB) is influenced by both genetic and shared environmental factors. Could these results be replicated using full-siblings and half-siblings? METHOD: In 911 009 full-siblings reared together (FSRT), 41 872 half-siblings reared together (HSRT) and 52 590 half-siblings reared apart (HSRA), CB was assessed from the Swedish Crime Register. Modeling, including testing for age differences and rearing status, was performed using the OpenMx package. RESULTS: Five sibling models were fitted examining FSRT and HSRT 0-2 years different in age, and both FSRT and HSRT, and FSRT, HSRT and HSRA 0-10 years different in age with and without a specified shared environment indexing age differences. Heritability estimates for CB ranged from 33 to 55% in females and 39 to 56% in males, similar to those found in our prior twin study on the same population. Estimates for the shared environment varied from 1 to 14% in females and 10 to 23% in males, lower than those estimated in the twin study. The specified shared environment indexed by sibling age differences was significant in all models tested. CONCLUSIONS: Heritability estimates for CB from full- and half-siblings closely approximated those found from twins in the same population, validating the twin method. Shared environmental estimates were lower, suggesting the presence of shared environmental factors for CB specific to twins. When rearing status can be assessed, full- and half-siblings offer an additional method for assessing the role of genetic and environmental factors in complex disorders. However, age differences in siblings may need to be included in the models.

Optimizing the information increase through the addition of relatives and genetic markers in identification and kinship cases.

In kinship testing powerful statistical results are usually obtained when genetic information is required to be shared between a set of individuals, under the assumption of one of the hypotheses. This is the case when the hypotheses parenthood or identity are compared with the hypothesis of no relatedness, even when only a pair of individuals is analyzed. In this work we will consider kinship problems where the sharing of genetic information is not required when a pair of individuals is analyzed, such as is the case of the hypotheses full-siblings or avuncular. Statistical evaluation was computed through the quantification of likelihood ratios, assuming the genotypic configuration of 100,000 simulated families, for each of the kinship problems analyzed: full-siblings vs. unrelated, full-siblings vs. half-siblings, half-siblings vs. unrelated, avuncular vs. unrelated, first cousins vs. unrelated, and half-first cousins vs. unrelated. For each of the six studied cases we have obtained results allowing us to weight the informative power impact of increasing the number of markers and of the addition of an extra individual, considering (a.) the use of different sets of STRs (from 8 to 35), and (b.) the introduction of a third undoubted relative. Based on these results we were able to provide recommendations for each case both on the minimal number of STRs to be used and on the third relative whose genetic analysis should be privileged.

Key individuals for discerning pedigrees belonging to the same autosomal kinship class.

The existence of pedigrees belonging to the same kinship class (i.e. indistinguishable through independent markers) is well known in the forensic community, and theoretical frameworks for autosomal and X-chromosomal markers were already developed for a pair of individuals. Nevertheless, studies for the cases where a greater number of individuals is available for testing are still lacking. With this work, we intend to pave the way for a theoretical and general framework, identifying the individuals/relatives that should be chosen to distinguish autosomal analyses between such pedigrees. In this work we identify the individuals/relatives that are non-informative for calculations (the pedigrees under discussion remaining indistinguishable independently of their genetic profile), as well as those that will likely be very informative, influencing the statistical outcome. For example, given the respective genotypes, to compare the likelihoods of the father of the individual B to be: (a.) the father, or (b.) a full-brother, of the individual A, the hypotheses H1: "The individual A is paternal half-sibling of the individual B", and H0: "The individual A is paternal uncle/aunt of the individual B" are considered. It is proved that considering just individuals A and B the hypotheses are equally likely. In this work we show that the same is also true for the case where the mother of B is available for testing, notwithstanding the hypotheses being differently weighted if the mother of A is considered. Similar considerations are done for other kinship hypotheses and/or individuals/relatives. Irrelevance of the genetic profile of some specific relatives are mathematically demonstrated, and data obtained from 20,000 simulated families are presented for the other cases.

Kin recognition by tadpoles and froglets of the wood frog Rana sylvatica.

We investigated kin recognition by the wood frog Rana sylvatica in blind laboratory experiments using spatial proximity as a recognition assay. Tadpoles were tested for the ability to discriminate between: 1) familiar full-sibs and unfamiliar non-kin, 2) unfamiliar paternal half-sibs and unfamiliar non-kin, and 3) familiar and unfamiliar full-sibs. Tadpoles discriminated full- and paternal half-sibs from unrelated conspecifics, but did not discriminate between familiar and unfamiliar full-sibs. Froglets from the same laboratory population were tested for the ability to discriminate between 1) familiar full-sibs and unfamiliar non-kin, and 2) unfamiliar paternal half-sibs and unfamiliar non-kin. Froglets preferentially associated with full- and half-sibs over unrelated conspecifics. Our results show that familiarity, i.e., prior association, is not necessary for kin recognition in tadpoles and froglets. The ability of tadpoles and froglets to recognize unfamiliar paternal half-sibs demonstrates that a common maternal factor is not necessary for kin recognition, and indicates that the recognition cue has a genetic component. Our results add to the increasing evidence that a variety of vertebrate and invertebrate animals have the ability to recognize unfamiliar kin by using genetically specified recognition cues.

Brief repot: Interactions with infants by full siblings, paternal half-siblings, and nonrelatives in a captive group of rhesus macaques (Macaca mulatta).

Six mother-infant pairs in a group of captive rhesus monkeys (Macaca mulatta) were observed for six months. "Infant grabs" by others and mothers' resistance to grabs were scored. More full siblings grabbed infants than either paternal half-siblings or nonrelatives. Mothers resisted grabbing by more nonrelatives than by paternal half-siblings. Although the maternal effect suggested by full sib-infant interactions is expected, the paternal effect revealed by mothers' tolerance of paternal half-sibs, but not full siblings, over nonrelatives is unexpected.