There is now compelling evidence that psychosocial stress is a cause of reproductive suppression in humans. However, women continue to conceive in the harshest conditions of war, poverty, or famine, suggesting that suppression can be bypassed. The reproductive suppression model (RSM) proposes that natural selection should favor factors that reliably predict conditions for reproduction. In this study, we examine two such factors, age and social position, in women undergoing fertility treatment. We hypothesized that stress-related reproductive suppression would be more likely in younger compared to older women and in women in lower compared to higher social positions. The final sample consisted of 818 women undergoing fertility treatment. Psychosocial stress and sociodemographic data were collected prior to the start of treatment (Time 1), whereas fertility, as indexed by pregnancy or live birth, was assessed 12 months later (Time 2). The results showed that younger women were four times more likely to suppress than older women, and that unskilled and manual workers were more likely to suppress than those in middle social positions (e.g., white collar workers). However, significant associations between stress and fertility were also observed for women in higher social positions (e.g., professionals and executives). The findings provide support for the RSM.