Sarah Hill: A research psychologist and professor specializing in evolutionary psychology and women's health, and author of the book on how hormonal birth control changes the brain.
What this episode covers
Sarah Hill walks through the science of how the contraceptive pill, by flatlining a woman's natural hormone cycle, can change her sexual desire, partner preferences, emotional states, stress (cortisol) response and ability to build muscle. She frames it within evolutionary psychology, explaining why women historically prefer high-status, high-resource partners and why men are wired for risk and status-seeking. The conversation covers the modern 'mating crisis' driven by women out-educating men, fertility-window shifts in attraction, the testosterone decline in fathers, and the real risk that a partner chosen on the pill may feel differently once off it. Hill also raises serious mental-health concerns for teenage girls on the pill and argues women need better contraceptive options than synthetic hormones.
The guest's own work
This Is Your Brain on Birth Control: How the Pill Changes Everything
Sarah Hill
“now it's called this is your brain on birth control how the pill changes everything”— Sarah Hill
Also referenced (named, not recommended)
All the Single Ladies
Rebecca Traister
“there's a wonderful um book called all the single ladies that is about this very phenomenon”— Sarah Hill
Barbie
Greta Gerwig
“I think that the Barbie movie was you know sort of got at some of these kinds of issues”— Sarah Hill
Nexplanon
Merck
“here in the US the one that people are on is called nexplanon and that gives a same it gives a daily dose of a synthetic progesterone”— Sarah Hill
Big reveals from this episode
- Women partnered to attractive men grew MORE attracted after quitting the pill, while those with less attractive partners grew less attracted and less satisfied.
- Hill argues the pill 'changes everything' for society by letting women plan their lives, fueling the rise of female college attendance.
- Hill reveals she was on hormonal birth control for over a decade and felt like she 'woke up' three months after stopping.
- Cites a longitudinal study showing real shifts in women's attraction to their partners after discontinuing the pill.
- Speculates the modern male 'testosterone crisis' could partly stem from so many women being on hormonal birth control.
- Notes a study where pill users were 50% more likely to be diagnosed with depression and twice as likely to attempt suicide.
- Warns teenage brains on the pill face unknown developmental risks because hormones coordinate puberty's brain remodeling.
- Bartlett shares his own relationship ended over his partner's lost libido, which returned after she came off the pill.
Worth remembering
- The 'Bateman principle': a man's fitness rises with each new partner, while a woman's reproductive output tops out after one.
- Estrogen surges around day 9 of the cycle and peaks at ovulation near day 14, sharpening women's preference for masculine cues.
- Testosterone is immunosuppressive, so high-testosterone features signal an immune system strong enough to handle the suppression.
- Men with higher testosterone are more likely to be married a year later; testosterone dips when men partner up and again when they have kids.
- Physical attractiveness predicts a woman's upward social mobility in the US more strongly than education or socioeconomic origin.
- Women on hormonal birth control have free testosterone levels about 60% lower than naturally cycling peers.
- In a classic University of Florida study, ~75-80% of men agreed to casual sex with an attractive stranger versus 0% of women.
- Pill users show a blunted or absent cortisol stress response, similar to the pattern seen in people with PTSD or trauma.
- New research finds pill users build less muscle than naturally cycling women doing identical workouts over 12 weeks.
- Men's testosterone shifts dynamically with environmental cues like attractive women, sports wins, and even the presence of a weapon.