"A lack of women during men’s teenage years still haunts their health decades later." The Economist reports on a surprising study that hints at an important formative sexual period. "It is now well established that marriage has a beneficial effect on health and survival. Since women are traditionally the caregivers, these benefits accrue especially to men. If there are fewer potential mates around, men may delay marriage or forgo it entirely, losing out on these nuptial niceties. In addition, with more men and fewer single women, the intense competition for a mate is likely to be stressful. Such early-life stress is known to have effects on health that can last for years."