Depression in the next generation is related with maternal behaviors: A cross-comparison by alternating rat's mother care.

This study investigated the potential impacts of depressive rats' maternal behavior as an early life stress on the outcome of offspring as an adulthood. Offspring from the same mother were divided into two groups, half of them were fostered or remained by a depressive mother, and the other half remained or fostered by a control mother, respectively. The results showed that offspring fostered by depressive mothers presented significant depressive behaviors. Meanwhile, depressive mothers engaged in more grooming during the light cycle, but less off-the-pup behavior during the dark phase. In conclusion, offspring exposed to a postnatal depressive maternal environment developed a depressive-like behavior. Contrarily, postpartum maternal behaviors play an essential role, which might determine the outcome of the next generation. Furthermore, the appropriate timing of postpartum maternal caring sequences, which might eliminate prenatal stressful influences, was recognized and might be a promising approach for reducing children's predisposition to mental disorders in their life time.

Genotypic sex shapes maternal care in the African pygmy mouse, Mus minutoides.

Sexually dimorphic behaviours, such as parental care, have long been thought to be mainly driven by gonadal hormones. In the past two decades, a few studies have challenged this view, highlighting the direct influence of the sex chromosome complement (XX versus XY or ZZ versus ZW). The African pygmy mouse, Mus minutoides, is a wild mouse species with naturally occurring XY sex reversal induced by a third, feminizing X* chromosome, leading to three female genotypes: XX, XX* and X*Y. Here, we show that sex reversal in X*Y females shapes a divergent maternal care strategy (maternal aggression, pup retrieval and nesting behaviours) from both XX and XX* females. Although neuroanatomical investigations were inconclusive, we show that the dopaminergic system in the anteroventral periventricular nucleus of the hypothalamus is worth investigating further as it may support differences in pup retrieval behaviour between females. Combining behaviours and neurobiology in a rodent subject to natural selection, we evaluate potential candidates for the neural basis of maternal behaviours and strengthen the underestimated role of the sex chromosomes in shaping sex differences in brain and behaviours. All things considered, we further highlight the emergence of a third sexual phenotype, challenging the binary view of phenotypic sexes.

Effect of Educational Intervention Based on Self-Efficacy Theory on the Caring Behaviour of Mothers Who Have Children With Cancer.

Self-efficacy, as one of the concepts of the empowerment model, plays a role in increasing caring behaviour. Accordingly, our study aimed to evaluate the effect of educational intervention based on self-efficacy theory on the caring behaviour of mothers who have children with cancer. This quasi-experimental study was conducted on all mothers (N = 86) of children with cancer undergoing chemotherapy who were referred to Bandar Abbas Children's Hospital. All mothers participated in 10 training sessions based on the four foundations of self-efficacy theory. The results indicated a significant increase in the mean score of mothers' self-efficacy at first and second follow-ups respectively by 10.2 and 10.9 after intervention (P < 0.001). Furthermore, the mean score of caring behaviour was increased after the intervention for the first and second follow ups by 24.6 and 25.9 from the baseline respectively (P < 0.001). The results of the present study indicated that an educational program for mothers increased their caring behaviour and self-efficacy with the increase of self-efficacy, mothers' caring behaviour was promoted. Authorities and practitioners are suggested to pay more attention to designing educational programs based on health models and theories.

Neural circuitry for maternal oxytocin release induced by infant cries.

Oxytocin is a neuropeptide that is important for maternal physiology and childcare, including parturition and milk ejection during nursing1-6. Suckling triggers the release of oxytocin, but other sensory cues-specifically, infant cries-can increase the levels of oxytocin in new human mothers7, which indicates that cries can activate hypothalamic oxytocin neurons. Here we describe a neural circuit that routes auditory information about infant vocalizations to mouse oxytocin neurons. We performed in vivo electrophysiological recordings and photometry from identified oxytocin neurons in awake maternal mice that were presented with pup calls. We found that oxytocin neurons responded to pup vocalizations, but not to pure tones, through input from the posterior intralaminar thalamus, and that repetitive thalamic stimulation induced lasting disinhibition of oxytocin neurons. This circuit gates central oxytocin release and maternal behaviour in response to calls, providing a mechanism for the integration of sensory cues from the offspring in maternal endocrine networks to ensure modulation of brain state for efficient parenting.

Protecting the future child: Foetal alcohol spectrum disorder, easy rescue and the regulation of maternal behaviour.

This paper argues that social contexts of inequality are crucial to understanding the ethics of gestational harm and responsibility. Recent debates on gestational harm have largely ignored the social context of gestators, including contexts of inequality and injustice. This can reinforce existing social injustices arising from colonialism, socio-economic inequality and racism, for example, through increased regulation of maternal behaviour. To demonstrate this, I focus on the related notions of the 'future child' and an obligation of easy rescue, which have been used to discuss the ethics of gestational harm in the context of alcohol consumption during gestation and foetal alcohol spectrum disorder (FASD). I use a feminist perspective to evaluate these ideas and conclude that anyone concerned with remediation of social injustice has good reason to be suspicious of the notion of the future child in the context of gestational harm.

Effects of repetitive pinprick stimulation on preterm offspring: Alterations in nociceptive responses and inflammatory hypersensitivity in adulthood.

INTRODUCTION: This study investigates the effects of repetitive pinprick stimulation on preterm offspring and its impact on nociceptive responses and inflammatory hypersensitivity in adulthood. OBJECTIVES: The objective is to shed light on the potential long-term consequences of neonatal pain and prematurity on sensory processing. METHODS: Term and preterm rats were subjected to repetitive pinprick (PP) stimulation or control (CC) during the neonatal period. Adult rats received CFA injection to induce inflammatory hypersensitivity, and mechanical hypersensitivity was measured. Gender differences in inflammatory hypersensitivity were also examined. Maternal behavior, litter weight, and offspring growth were monitored to assess any potential influences of the stimulation on these parameters. RESULTS: In preterm rats, the PP stimulation did not affect baseline thresholds to mechanical stimuli, but increased mechanical hypersensitivity after CFA injection in adult rats. Females exhibited greater inflammatory hypersensitivity compared to males. Maternal behavior, litter weight, and offspring growth were not influenced by the stimulation. PP stimulation during the neonatal period led to changes in nociceptive responses in adulthood, potentially altering sensory processing. CONCLUSION: PP stimulation in preterm rats during the neonatal period resulted in changes in nociceptive responses in adulthood, leading to increased inflammatory hypersensitivity. The study emphasizes how early development can significantly impact sensory processing and further highlights the potential long-term consequences of prematurity and neonatal pain on this processing.

Enhanced maternal behaviors in a mouse model of congenital blindness.

In mammals, mothering is one of the most important prosocial female behavior to promote survival, proper sensorimotor, and emotional development of the offspring. Different intrinsic and extrinsic factors can initiate and maintain these behaviors, such as hormonal, cerebral, and sensory changes. Infant cues also stimulate multisensory systems and orchestrate complex maternal responsiveness. To understand the maternal behavior driven by complex sensory interactions, it is necessary to comprehend the individual sensory systems by taking out other senses. An excellent model for investigating sensory regulation of maternal behavior is a murine model of congenital blindness, the ZRDBA mice, where both an anophthalmic and sighted mice are generated from the same litter. Therefore, this study aims to assess whether visual inputs are essential to driving maternal behaviors in mice. Maternal behaviors were assessed using three behavioral tests, including the pup retrieval test, the home cage maternal behavior test, and the maternal aggression test. Our results show that blind mothers (1) took less time to retrieve their offspring inside the nest, (2) spent more time nursing and licking their offspring in the second- and third-week postpartum, and (3) exhibited faster aggressive behaviors when exposed to an intruder male, compared to the sighted counterparts. This study provides evidence that congenitally blind mothers show more motivation to retrieve the pups, care, and protection towards their pups than sighted ones, likely due to a phenomenon of sensory compensation.

Father's care uniquely influences male neurodevelopment.

Mammalian infants depend on parental care for survival, with numerous consequences for their behavioral development. We investigated the epigenetic and neurodevelopmental mechanisms mediating the impact of early biparental care on development of alloparenting behavior, or caring for offspring that are not one's own. We find that receiving high parental care early in life leads to slower epigenetic aging of both sexes and widespread male-specific differential expression of genes related to synaptic transmission and autism in the nucleus accumbens. Examination of parental care composition indicates that high-care fathers promote a male-specific increase in excitatory synapses and increases in pup retrieval behavior as juveniles. Interestingly, females raised by high-care fathers have the opposite behavioral response and display fewer pup retrievals. These results support the concept that neurodevelopmental trajectories are programmed by different features of early-life parental care and reveal that male neurodevelopmental processes are uniquely sensitive to care by fathers.

Negative versus withdrawn maternal behavior: Differential associations with infant gray and white matter during the first 2 years of life.

Distinct neural effects of threat versus deprivation emerge by childhood, but little data are available in infancy. Withdrawn versus negative parenting may represent dimensionalized indices of early deprivation versus early threat, but no studies have assessed neural correlates of withdrawn versus negative parenting in infancy. The objective of this study was to separately assess the links of maternal withdrawal and maternal negative/inappropriate interaction with infant gray matter volume (GMV), white matter volume (WMV), amygdala, and hippocampal volume. Participants included 57 mother-infant dyads. Withdrawn and negative/inappropriate aspects of maternal behavior were coded from the Still-Face Paradigm at four months infant age. Between 4 and 24 months (M age = 12.28 months, SD = 5.99), during natural sleep, infants completed an MRI using a 3.0 T Siemens scanner. GMV, WMV, amygdala, and hippocampal volumes were extracted via automated segmentation. Diffusion weighted imaging volumetric data were also generated for major white matter tracts. Maternal withdrawal was associated with lower infant GMV. Negative/inappropriate interaction was associated with lower overall WMV. Age did not moderate these effects. Maternal withdrawal was further associated with reduced right hippocampal volume at older ages. Exploratory analyses of white matter tracts found that negative/inappropriate maternal behavior was specifically associated with reduced volume in the ventral language network. Results suggest that quality of day-to-day parenting is related to infant brain volumes during the first two years of life, with distinct aspects of interaction associated with distinct neural effects.

Exploring the accuracy of self-reported maternal and newborn care in select studies from low and middle-income country settings: do respondent and facility characteristics affect measurement?

BACKGROUND: Accurate data on the receipt of essential maternal and newborn health interventions is necessary to interpret and address gaps in effective coverage. Validation results of commonly used content and quality of care indicators routinely implemented in international survey programs vary across settings. We assessed how respondent and facility characteristics influenced the accuracy of women's recall of interventions received in the antenatal and postnatal periods. METHODS: We synthesized reporting accuracy using data from a known sample of validation studies conducted in Sub-Saharan Africa and Southeast Asia, which assessed the validity of women's self-report of received antenatal care (ANC) (N = 3 studies, 3,169 participants) and postnatal care (PNC) (N = 5 studies, 2,462 participants) compared to direct observation. For each study, indicator sensitivity and specificity are presented with 95% confidence intervals. Univariate fixed effects and bivariate random effects models were used to examine whether respondent characteristics (e.g., age group, parity, education level), facility quality, or intervention coverage level influenced the accuracy of women's recall of whether interventions were received. RESULTS: Intervention coverage was associated with reporting accuracy across studies for the majority (9 of 12) of PNC indicators. Increasing intervention coverage was associated with poorer specificity for 8 indicators and improved sensitivity for 6 indicators. Reporting accuracy for ANC or PNC indicators did not consistently differ by any other respondent or facility characteristic. CONCLUSIONS: High intervention coverage may contribute to higher false positive reporting (poorer specificity) among women who receive facility-based maternal and newborn care while low intervention coverage may contribute to false negative reporting (lower sensitivity). While replication in other country and facility settings is warranted, results suggest that monitoring efforts should consider the context of care when interpreting national estimates of intervention coverage.

Explaining the Link Between Paternal Socioeconomic Position and Small for Gestational Age Birth: The Effect of Maternal Unhealthy Behaviors.

OBJECTIVE: To determine the proportion of small for gestational age (weight < 10th percentile, SGA) births among fathers with lifelong low (compared to high) socioeconomic position (SEP) attributable to white and African-American women's unhealthy pregnancy-related behaviors. METHODS: Oaxaca-Blinder decomposition methods were conducted on the Illinois transgenerational dataset of infants (1989-1991) and their Chicago-born parents (1956-1976) with appended US census income data. The neighborhood income of father's residence at the time of his birth and at the time of his infant's birth were used to estimate his lifetime SEP. Maternal unhealthy pregnancy-related behaviors were defined as cigarette smoking, inadequate prenatal care, and/or low weight gain during pregnancy. RESULTS: Among African-American women, births (n = 4426) to fathers with lifetime low SEP had an SGA rate of 14.8% compared to 12.1% for those (n = 365) born to fathers with lifetime high SEP (p < 0.0001). Among white women, births (n = 1430) to fathers with lifetime low SEP had an SGA rate of 9.8% compared to 6.2% for those (n = 9141) born to fathers with lifetime high SEP (p < 0.0001). Adjusting for maternal age, marital status, education, and parity, African-American and white women's unhealthy pregnancy behaviors accounted for 25% and 33%, respectively, of the disparity in SGA rates among infants of lifetime low (compared to high) SEP fathers. CONCLUSION: A significant proportion of the disparity in SGA rates between fathers with lifelong low (compared to high) SEP is explained in both races by maternal unhealthy pregnancy behaviors.

An intensive longitudinal investigation of maternal and infant touching patterns across context and throughout the first 9-months of life.

Touch is a central component of mothers' and infants' everyday interactions and the formation of a healthy mother-infant relationship. Twelve mothers and their full-term infants from the Midwest, USA participated in the present study, which examined the quality and quantity of their touching behaviors longitudinally at 1-, 3-, 5-, 7-, and 9-months postpartum and within two normative interaction contexts (face-to-face, floor play). Findings revealed that mothers' and infants' individual touch patterns, varied according to context, infant age (time), and the specific type of touch examined. At 1-month postpartum, dyads coordinated their touch via behavioral matching and were especially reliant on rudimentary types of touch with soothing and regulatory properties (static/motionless touch, stroking). As infants aged to 9-months, dyads transitioned to a more complex form of tactile synchrony characterized by the parallel use of complementary types of touch (grasp, poke, pull). This evolution of tactile synchrony may reflect infants' growing behavioral repertoire and increased capacity to use more refined forms of touch. To our knowledge, this study was the first of its kind, uniquely contributing to the scant knowledge about the development of mother-infant touch and synchrony and offering direct implications for early care practices and infant health and well-being.

Antagonistic circuits mediating infanticide and maternal care in female mice.

In many species, including mice, female animals show markedly different pup-directed behaviours based on their reproductive state1,2. Naive wild female mice often kill pups, while lactating female mice are dedicated to pup caring3,4. The neural mechanisms that mediate infanticide and its switch to maternal behaviours during motherhood remain unclear. Here, on the basis of the hypothesis that maternal and infanticidal behaviours are supported by distinct and competing neural circuits5,6, we use the medial preoptic area (MPOA), a key site for maternal behaviours7-11, as a starting point and identify three MPOA-connected brain regions that drive differential negative pup-directed behaviours. Functional manipulation and in vivo recording reveal that oestrogen receptor α (ESR1)-expressing cells in the principal nucleus of the bed nucleus of stria terminalis (BNSTprESR1) are necessary, sufficient and naturally activated during infanticide in female mice. MPOAESR1 and BNSTprESR1 neurons form reciprocal inhibition to control the balance between positive and negative infant-directed behaviours. During motherhood, MPOAESR1 and BNSTprESR1 cells change their excitability in opposite directions, supporting a marked switch of female behaviours towards the young.

One Day Away from Mum has Lifelong Consequences on Brain and Behaviour.

This chapter presents a brief overview of attachment theory and discusses the importance of the neonatal period in shaping an individual's physiological and behavioural responses to stress later in life, with a focus on the role of the parent-infant relationship, particularly in rodents. In rodents, the role of maternal behaviours goes far beyond nutrition, thermoregulation and excretion, acting as hidden regulators of the pup's physiology and development. In this review, we will discuss the inhibitory role of specific maternal behaviours on the ACTH and corticosterone (CORT) stress response. The interest of our group to explore the long-term consequences of maternal deprivation for 24 h (DEP) at different ages (3 days and 11 days) in rats was sparked by its opposite effects on ACTH and CORT levels. In early adulthood, DEP3 animals (males and females alike) show greater negative impact on affective behaviours and stress related parameters than DEP11, indicating that the latter is more resilient in tests of anxiety-like behaviour. These findings create an opportunity to explore the neurobiological underpinnings of vulnerability and resilience to stress-related disorders. The chapter also provides a brief historical overview and highlights the relevance of attachment theory, and how DEP helps to understand the effects of childhood parental loss as a risk factor for depression, schizophrenia, and PTSD in both childhood and adulthood. Furthermore, we present the concept of environmental enrichment (EE), its effects on stress responses and related behavioural changes and its benefits for rats previously subjected to DEP, along with the clinical implications of DEP and EE.

Changes in patterns of Early Mother-Child Interaction: A longitudinal study of the first 18 months of life.

OBJECTIVE: The main objective of the present longitudinal study is to describe the progression of early adult-child interactions between the first and second years of life. Changes identified in interactions are described, focusing on both the qualitative aspects of maternal responses, as well as maternal response latency to the child's behavior using a microanalytical methodology that collected data on maternal and child behavior in real-time without losing sight of the temporal dimension. PARTICIPANTS: This study examined 52 mother-child dyads from intact families that presented no psychological, social, or biological risk factors at 6, 12 and 18 months of age. INSTRUMENT: CITMI-R (early mother-child interaction coding system, revised edition) was used to assess early mother-infant interactions during free play sessions between mother and child the. RESULTS: The results indicate that some components of maternal sensitivity improve as children progress towards the second year of life, detecting an increase in sensitive maternal behavior and a decrease in intrusive behavior in the evolutive observed period; moreover, regarding latency of maternal response, we observed that mothers of older children give more time for their children to explore, which stimulates autonomy. Finally, the implication of these results for intervention directed to optimizing early adult-child interactions are addressed.

Does a mother's childbirth experience influence her perceptions of her baby's behaviour? A qualitative interview study.

BACKGROUND: Childbirth has become increasingly medicalised, which may impact on the mother's birth experience and her newborn infant's physiology and behaviour. Although associations have been found between a mother's subjective birth experience and her baby's temperament, there is limited qualitative evidence around how and why this may occur. OBJECTIVES: This qualitative study aimed to explore mothers' childbirth and postnatal experiences, perceptions of their baby's early behavioural style, and whether they saw these as related. METHODS: A qualitative semi-structured interview schedule collected rich in-depth data. Twenty-two healthy mothers over 18 years of age and with healthy infants aged 0-12 months born at term, were recruited from Southwest regions of England and Wales. Thematic analysis was performed on the data. RESULTS: Mothers experienced childbirth as a momentous physical and psychological process. However, they did not necessarily perceive the birth as affecting their baby's early behaviour or temperament. While some mothers drew a direct relationship, such as linking a straightforward birth to a calm infant, others did not make an explicit connection, especially those who experienced a challenging birth and postnatal period. Nevertheless, mothers who had a difficult or medicalised birth sometimes reported unsettled infant behaviour. It is possible that mothers who feel anxious or depressed after a challenging birth, or those without a good support network, may simply perceive their infant as more unsettled. Equally, mothers who have been well-supported and experienced an easier birth could be more likely to perceive their baby as easier to care for. CONCLUSIONS: Childbirth is a physical and psychological event that may affect mother-infant wellbeing and influence maternal perceptions of early infant temperament. The present findings add to prior evidence, reinforcing the importance of providing good physical and emotional support during and after childbirth to encourage positive mother-infant outcomes.

Sex-specific effects of chronic paternal stress on offspring development are partially mediated via mothers.

Paternal stress exposure is known to impact the development of stress-related behaviors in offspring. Previous work has highlighted the importance of sperm mediated factors, such as RNAs, in transmitting the effects of parental stress. However, a key unanswered question is whether mothers behavior could drive or modulate the transmission of paternal stress effects on offspring development. Here we investigate how chronic variable stress in Balb/C mice influences the sex-specific development of anxiety- and depression-like neural and behavioral development in offspring. Moreover, we examined how stressed fathers influenced mate maternal investment towards their offspring and how this may modulate the transmission of paternal stress effects on offspring. We show that paternal stress leads to sex-specific effects on offspring behavior. Males that are chronically stressed sire female offspring that show increased anxiety and depression-like behaviors. However, male offspring of stressed fathers show reductions in anxiety- and depression-behaviors and are generally more exploratory. Moreover, we show that females mated with stressed males gain less weight during pregnancy and provide less care towards their offspring which additionally influenced offspring development. These data indicate that paternal stress can influence offspring development both directly and indirectly via changes in mothers, with implications for sex-specific offspring development.

Brief versus long maternal separation in lactating rats: Consequences on maternal behavior, emotionality, and brain oxytocin receptor binding.

Maternal separation is a widely used animal model to study early life adversity in offspring. However, only a few studies have focused on the impact of disrupting the maternal bond from the mother's perspective. Such studies reveal alterations in behavior, whereas the underlying neuroendocrine mechanisms remain largely unknown. In this study, we compared the consequences of daily brief maternal separation (BMS; 15 min) versus long maternal separation (LMS; 180 min) during the first week postpartum with respect to behavioral and neuroendocrine changes in lactating Sprague-Dawley dams. Mothers were tested for their maternal care before and after separation, maternal motivation to retrieve pups, as well as anxiety-related and stress-coping behaviors. In addition, we analyzed their basal plasma corticosterone levels and oxytocin receptor binding in selected brain regions of the limbic system and maternal network. LMS dams showed higher levels of behavioral alterations compared to BMS and non-maternally separated (NMS) dams, including increased licking and grooming of the pups and decreased maternal motivation. Anxiety-related behavior was not affected by either separation paradigm, whereas passive stress-coping behavior tended to increase in the LMS group. Plasma corticosterone concentrations were not different between groups. Oxytocin receptor binding was higher in the medial preoptic area and tended to be higher in the prelimbic cortex of LMS dams, only. Our results demonstrate that especially daily prolonged maternal separation impacts on the mothers' behavior and oxytocin system, which suggests that enhanced oxytocin receptor binding could be a compensatory mechanism for potentially decreased central oxytocin release due to limited pup contact.

Duration of Breastfeeding and Supportive Paternal Caregiving in Early Childhood and the Potential Mediating Function of Maternal Caregiving.

OBJECTIVE: Supportive paternal caregiving is influenced by contextual factors, including maternal caregiving behaviors. Although longer periods of breastfeeding have been found to be associated with higher levels of maternal supportive parenting, it remains unknown whether the benefits of breastfeeding also extend to fathers' supportive caregiving. This study tested the indirect relation between the duration of breastfeeding and paternal supportive parenting through maternal supportive parenting. METHODS: Participating families (N = 623) were from the Behavior Outlook Norwegian Developmental Study, a population-based longitudinal study in Southeast Norway. Path analysis was used to test associations between the duration of breastfeeding in the first year (parent report) and paternal supportive parenting (observed, 36 months), as potentially mediated by maternal supportive parenting (observed, 24 months). RESULTS: After controlling for sociodemographic and birth factors, a longer duration of breastfeeding was indirectly associated with higher levels of observed paternal supportive parenting through maternal supportive parenting. CONCLUSION: The current findings suggest that the longer breastfeeding duration during the first year of life (i.e., infancy) might have important implications for both maternal and paternal supportive parenting in toddlerhood.

Variation in the serotonin transporter genotype is associated with maternal restraint and rejection of infants: A nonhuman primate (Macaca mulatta) model.

Studies show that maternal behaviors are mediated by the bivariate serotonin transporter (5-HTT) genotype, although the findings are mixed, with some studies showing that mothers with the s allele exhibit increased maternal sensitivity, while other studies show that mothers with the s allele show decreased maternal sensitivity. Nonhuman primate studies offer increased control over extraneous variables and may contribute to a better understanding of the effects of the 5-HTT genotype on maternal sensitivity. This study assesses the influence of 5-HTT genotype variation on maternal sensitivity in parenting in 125 rhesus macaque mothers (Macaca mulatta) during the first three-months of their infants' lives, an age well before typical infants undergo weaning. Mothers were genotyped for the 5-HTT genotype and maternal behaviors were collected, including neglectfulness, sensitivity, and premature rejections during undisturbed social interactions. Results showed that mothers homozygous for the s allele rejected their infants the most and restrained their infants the least, an indication that mothers with the s allele are more likely to neglect their infants' psychological and physical needs. These findings suggest that, at an age when an infant's needs are based on warmth, security, and protection, mothers with an s allele exhibit less sensitive maternal behaviors. High rates of rejections and low rates of restraints are behaviors that typically characterize premature weaning and are inappropriate for their infant's young age. This study is an important step in understanding the etiology of variability in maternal warmth and care, and further suggests that maternal 5-HTT genotype should be examined in studies assessing genetic influences on variation in maternal sensitivity, and ultimately, mother-infant attachment quality.