More Females are Born in Times of Stress

A stress-related decline in the sex ratio is no anomaly, but a biological mechanism that evolved to keep the species going, according to Ralph Catalano, professor of public health at the University of California, Berkeley. “From an evolutionary perspective, in stressful eras it’s a smarter bet to have a female child than a male child. A daughter is more apt to provide you with grandchildren,” Catalano tells me. In hard times, he explains, weak males are less likely to survive and to reproduce...