Dr. Ron’s Research Review – June 18, 2014

© 2014

This week’s research review focuses on testosterone and fatherhood or motherhood.

Marriage and motherhood are associated with lower testosterone concentrations in women. Testosterone was measured in 195 reproductive-age Norwegian women. Mothers of young children (age </=3) had 14% lower testosterone than childless women and 19% lower testosterone than women who only had children over age 3. Among mothers, age of the youngest child strongly predicted testosterone levels. There was a trend towards lower testosterone among married women compared to unmarried women.  (Barrett et al., 2013)

Testosterone levels are negatively associated with fatherhood in males, but positively related to offspring count in fathers. In a large sample of elderly American men (n = 754) and women (n = 669), fathers had lower T levels than men who report no children. Among fathers, T levels were positively associated with the number of children a man reports close to the end of his lifespan. In contrast, T was not associated with either motherhood or the number of children women had. (Pollet et al., 2013)

Dr. Ron


 

Articles

Marriage and motherhood are associated with lower testosterone concentrations in women.
(Barrett et al., 2013) Download
Testosterone has been hypothesized to modulate the trade-off between mating and parenting effort in males. Indeed, evidence from humans and other pair-bonded species suggests that fathers and men in committed relationships have lower testosterone levels than single men and men with no children. To date, only one published study has examined testosterone in relation to motherhood, finding that mothers of young children have lower testosterone than non-mothers. Here, we examine this question in 195 reproductive-age Norwegian women. Testosterone was measured in morning serum samples taken during the early follicular phase of the menstrual cycle, and marital and maternal status were assessed by questionnaire. Mothers of young children (age </=3) had 14% lower testosterone than childless women and 19% lower testosterone than women who only had children over age 3. Among mothers, age of the youngest child strongly predicted testosterone levels. There was a trend towards lower testosterone among married women compared to unmarried women. All analyses controlled for body mass index (BMI), age, type of testosterone assay, and time of serum sample collection. This is the first study to look at testosterone concentrations in relation to marriage and motherhood in Western women, and it suggests that testosterone may differ with marital and maternal status in women, providing further corroboration of previous findings in both sexes.

Testosterone levels are negatively associated with fatherhood [corrected] in males, but positively related to offspring count in fathers.
(Pollet et al., 2013) Download
Variation in testosterone (T) is thought to affect the allocation of effort between reproductive and parenting strategies. Here, using a large sample of elderly American men (n = 754) and women (n = 669) we examined the relationship between T and self-reported parenthood, as well as the relationship between T and number of reported children. Results supported previous findings from the literature, showing that fathers had lower T levels than men who report no children. Furthermore, we found that among fathers T levels were positively associated with the number of children a man reports close to the end of his lifespan. Results were maintained when controlling for a number of relevant factors such as time of T sampling, participant age, educational attainment, BMI, marital status and reported number of sex partners. In contrast, T was not associated with either motherhood or the number of children women had, suggesting that, at least in this sample, T does not influence the allocation of effort between reproductive and parenting strategies among women. Findings from this study contribute to the growing body of literature suggesting that, among men, pair bonding and paternal care are associated with lower T levels, while searching and acquiring sex partners is associated with higher T levels.


References

Barrett, ES, et al. (2013), ‘Marriage and motherhood are associated with lower testosterone concentrations in women.’, Horm Behav, 63 (1), 72-79. PubMedID: 23123222
Pollet, TV, KD Cobey, and L van der Meij (2013), ‘Testosterone levels are negatively associated with fatherhood [corrected] in males, but positively related to offspring count in fathers.’, PLoS One, 8 (4), e60018. PubMedID: 23573228