Do fathers have lower testosterone? 5 of 9 partly agree

Do fathers have lower testosterone?

The claim checked: Hands-on fathers see their testosterone drop by about 25% Hear it at 9:44

What do the studies say?

Leaning for

Four studies found fathers, or men who did more childcare, had lower testosterone. In Cebu, childcare went with 25% lower evening testosterone. Five found a smaller or less certain drop. A pooled analysis called the combined effects small.

Computed from 9 studies that test this point, each judged by two readers, in full. 10 more studies are waiting for a full read and do not count yet.

The study behind the claim tested something else. See what it tested

What was said on the podcast?

“So typically men when their hands on as fathers show about a 25% drop in testosterone and some of the best studies of this have been done longitudinally in the Philippines.”

Darby Saxbe, a guest on The Diary of a CEO · Testosterone Expert: The Truth About DAD BOD & Why Women Find Fathers More Attractive! · 9:44 on YouTube

The study behind the claim The retelling overstates it

What did the study actually test?

On tape: about a 25% drop, longitudinal studies in the Philippines. This study matches: waking testosterone fell by a median 26% in men who became partnered fathers. Longitudinal evidence that fatherhood decreases testosterone in human males. Proc Natl Acad Sci U S A, 2011. Longitudinal cohort (Cebu Longitudinal Health and Nutrition Survey), testosterone measured in 2005 and 4.5 years later, 624 young men in Cebu, the Philippines, about 21.5 years old and single nonfathers at baseline.

What was saidWhat the study did

What was given Matches Becoming a hands-on father Becoming a partnered father, and hours of daily childcare

Compared with Matches Men before fatherhood Men who stayed single nonfathers

What was measured Matches About a 25% drop in testosterone Change in waking and evening testosterone over 4.5 years

Who took part Differs Men who become fathers 624 young men in Cebu, the Philippines

What it found

“Men who became partnered fathers then experienced large declines in waking (median: −26%) and evening (median: −34%) T, which were significantly greater than declines in single nonfathers (P < 0.”

PMID 21911391

How the authors extend it

“Using longitudinal data, these findings show that T and reproductive strategy have bidirectional relationships in human males, with high T predicting subsequent mating success but then declining rapidly after men become fathers.”

PMID 21911391

This work was supported by the Wenner Gren Foundation (Grants 7356 and 8186), National Science Foundation (Grants BCS-0542182 and BCS-0962212), Interdisciplinary Obesity Center (Grant RR20649), and Center for Environmental Health and Susceptibility (Grant ES10126; Project 7-2004-E). Two readers agreed on the label, and the paper was read in full.

The point checked Leaning for

Becoming a father, especially a hands-on one, lowers men's testosterone (by about 25%)

Agree 4

other primary study · 2011 · cited on tape

“Consistent with this hypothesis, men who were both newly partnered and new fathers showed the largest declines in AM and PM T between 2005 and 2009 (Fig. 1 A and B), and their declines in both AM (median: −26%) and PM (median: −34%) T were significantly greater than the modest age-related declines in AM (median: −12%) and PM (median: −14%) T observed among single nonfathers (P < 0.001, n = 465; Fig. 1B and Tables S2 and S3).”

Longitudinal evidence that fatherhood decreases testosterone in human males. Proc Natl Acad Sci U S A
Who: Filipino men from the Cebu Longitudinal Health and Nutrition Survey, aged 21.5 at baseline and 26.0 at follow-up
PMID 21911391

other primary study · 2009

“Our cross-cultural data support this idea by showing that, among the Hadza, a group exhibiting high levels of paternal involvement, men caring for offspring maintain lower levels of testosterone than men who are not engaged in such care.”

Testosterone and paternal care in East African foragers and pastoralists. Proc Biol Sci
Who: Tanzanian men aged 17-60: Hadza foragers (high paternal care) and Datoga pastoralists (low paternal care)
PMID 18826936

other primary study · 2006

“In summary, our data show that Beijing fathers have lower testosterone levels than their unmarried male and married non-father counterparts.”

Fathers have lower salivary testosterone levels than unmarried men and married non-fathers in Beijing, China. Proc Biol Sci
Who: Chinese men aged 21-38 from a Beijing university setting
PMID 16543176

Show 1 more Show fewer

other primary study · 2009

“Although many of these associations were of similar magnitude, self-reported childcare had an especially strong relationship with evening T, being associated with a highly significant 25% lower T level.”

Fatherhood, pairbonding and testosterone in the Philippines. Horm Behav
Who: 890 young men aged 20.5-22.5 from the Cebu Longitudinal Health and Nutrition Survey birth cohort, Cebu City, Philippines (117 fathers)
PMID 19651129

Partly agree 5

other primary study · 2013

“Testosterone levels were also negatively correlated with caregiving [r(56) = −0.27, P < 0.05] (Fig. 1B).”

Testicular volume is inversely correlated with nurturing-related brain activity in human fathers. Proc Natl Acad Sci U S A
Who: US biological fathers aged 21-55 of children aged 1-2, cohabiting with the mother, Atlanta
PMID 24019499

pooled analysis · 2019

“Parental status and (higher) parenting quality were related to lower levels of testosterone, but according to conventional criteria combined effect sizes were small.”

Challenging the challenge hypothesis on testosterone in fathers: Limited meta-analytic support. Psychoneuroendocrinology
Who: Meta-analysis of studies of testosterone in males by parental status, parenting quality and reactivity to child stimuli
PMID 31541914

other primary study · 2022

“T decreased substantially from the prenatal to the postnatal period, whereas E2 levels remained the same.”

Is paternal oxytocin an oxymoron? Oxytocin, vasopressin, testosterone, oestradiol and cortisol in emerging fatherhood. Philos Trans R Soc Lond B Biol Sci
Who: 152 Dutch first-time fathers aged 25-56 cohabiting with the mother: 73 expectant fathers followed from pregnancy to postpartum and 79 new fathers seen postpartum only
PMID 35858109

Show 2 more Show fewer

other primary study · 2017

“Consistent with our previously reported results, fathers showed significant prenatal declines (slope by pregnancy weeks) in both testosterone, b = −0.27, t = 2.86, p = .005, and estradiol levels, b = −0.01, t = −2.00, p = .05.”

Prospective and dyadic associations between expectant parents' prenatal hormone changes and postpartum parenting outcomes. Dev Psychobiol
Who: 27 first-time expectant couples (men aged 20-42) in Michigan, mostly white, educated, married or engaged
PMID 27604815

other primary study · 2012

“We found that fathers who slept on the same surface as their children had significantly lower PM T and a significantly greater diurnal decline in T from waking (AM) to bedtime (PM) compared to men who slept solitarily.”

Does cosleeping contribute to lower testosterone levels in fathers? Evidence from the Philippines. PLoS One
Who: 362 fathers aged about 26 from the Cebu Longitudinal Health and Nutrition Survey, Philippines (17 solitary sleepers, 11 roomsharers, 334 same-surface cosleepers); 209 men who became fathers between 2005 and 2009 for longitudinal analysis
PMID 22957016

Disagree 0

None.