The results showed that the Inconsolable Doll task indeed triggered an increase in fathers’ testosterone levels. As front-line professionals and policy-makers consider the array of influences that may amplify the abuse risk of the parents they work with, an appreciation of that wider biopsychosocial picture may encourage less reductionistic characterizations of what collectively contributes to parent-child aggression. Earlier work indicated that stressors relate to fathers’ higher testosterone levels (Waldvogel & Ehrlert, 2018), and that those with both high testosterone levels and aggressive tendencies may not demonstrate effective emotion regulation (Kaldewaij et al., 2019). Thus, in contrast to earlier speculation that higher testosterone levels may interact to exacerbate lower SES to adversely affect behavior (Yildirim & Derksen, 2012a), we observed higher SES as a potential protective factor for fathers. These findings suggest higher SES conditions may reduce abuse risk despite higher testosterone levels. Contrary to popular belief, testosterone does not solely promote aggressive or dominant behaviors. However, this hormone plays a crucial role in various aspects of men’s health, including their parental behaviors. Fathers ranged in age from 23 to 42 years, with an average age of 32, while mothers had an average age of 30. Individuals with this trait tend to struggle with interpersonal relationships and regulating their own emotions. This design makes it impossible to say for certain that family life caused the testosterone differences. The study is also cross-sectional, meaning it looked at different men at a single point in time. It is possible that some participants were stepfathers, adoptive fathers, or other male relatives. Note that SES was significantly positively correlated with higher testosterone levels for both mothers and fathers. These APIMs simultaneously considered both "actor" effects on abuse risk (i.e., a parent’s testosterone level direct effects on their T3 abuse risk CAPI, AAPI-2, ReACCT) as well as "partner" effects (i.e., effects of a parent’s testosterone levels on their partner’s abuse risk). To further test the third, longitudinal RQ pertaining to abuse risk, we utilized MPlus 8.1 to examine testosterone levels in relation to abuse risk (CAPI, AAPI-2, ReACCT) across the four time points (path models that estimate lagged effects of stability in abuse risk across time). The Adult Adolescent Parenting Inventory-2 (AAPI-2; Bavolek & Keene, 2001) is an additional self-report measure of child abuse risk specifically designed to assess parenting beliefs and behaviors considered to reflect abusive parenting. The present study evaluated mothers’ and fathers’ testosterone levels in relation to personality characteristics of empathy and frustration tolerance as well as child abuse risk and observed parenting in a multimethod, longitudinal investigation. In an effort to identify biobehavioral indicators of physical abuse risk, the current study examined mothers’ and fathers’ salivary testosterone levels collected when their children were 18 months old as part of a prospective, longitudinal, multimethod study. In particular, research on mothers’ and fathers’ relationships with their sons and daughters indicates that parents have closer relationships with same gender offspring, particularly when they have both a daughter and a son, and that these gendered patterns become more pronounced as children age (Shanahan et al., 2007). At two years of age, children of these fathers tended to exhibit fewer prosocial behaviors, but only if the father experienced at least an average increase in testosterone levels when subjected to a stressful parenting task. One could speculate that, for women, individual differences in other hormones such as estrogens or oxytocin may be more relevant in biopsychosocial models of their abuse risk but such speculations await further study. Time points (T1, T2, T3, T4) in first column refer to measures of abuse risk (CAPI, AAPI-2, ReACCT in columns) at those time points Fathers’ self-reported dispositional empathy was not significantly related to their testosterone levels (in which only the association with T4 IRI scores were in the expected direction). Because controlling for age or SES would imply testosterone would need to account for incremental variance (which was not the intent of this study), neither was considered a covariate. For two-parent families, the order of which parent engaged the infant in the parent-child interaction first was counterbalanced. During free play, parents and infants were seated on a blanket on the floor; parents were instructed to play with their infant as they normally would but using only the standard set of provided age-appropriate toys while completing a brief form about their infant, which competed for their attention. During the task, parents hear and see a ticking clock of how late they are to induce time urgency. All participants live in or around Cebu City, the Philippines, where it is common for fathers to be involved in day-to-day care of their children (22). Because time and energy are finite (7), males in these species often face tradeoffs between conflicting behaviors related to mating and parenting. Prior research has shown that a father's involvement in their child's day-to-day life has powerful psychological effects on both parents. These parents tended to be more frustrated and aggravated by their children when teaching them. It appears that the sound of a baby crying sends emotional and hormonal messages to the parents who tend to encourage taking care of the child. The Parenting Stress Index (PSI; Abidin, 2012) Role Restriction is a subscale of the PSI, a self-report measure of perceived stress from parenting. During the novelty task, an assistant wearing a costume (e.g., "Shrek," first parent-child interaction, "Sulley" from Monsters, Inc., second interaction) entered the room and gradually approached the child within 2 feet while delivering a standard script. During caregiving, parents were asked to undress the infant, change the infants’ diaper, and redress the infant. Across several samples of varying risk, ReACCT Noncompliance scores demonstrated reliability and correlated with measures of abuse risk (CAPI, AAPI-2) and harsh and abusive physical discipline (Rodriguez, 2016). Because the child may have been noncompliant, the parent can remain "stuck" in a scene until the child complies; thus, the parent provides 20 total discipline responses across the 12 scenes. Parents are asked to select from 16 possible options how they would respond to the child’s compliance or noncompliance; some parent responses are adaptive (receiving positive weights) versus maladaptive (receiving negative weights)—e.g., physical and psychological aggression. In each scene, the parent is told they provided an instruction to the child to get ready to leave home and the child is reported to be either compliant or noncompliant.