His patients were having trouble conceiving, and he reckoned that their ovaries might do better after a short break from ovulating.

ECONOMIST: The Pill

Those who were ovulating rated the "dominant" men as sexiest, but there was no similar pattern among women at other stages of their menstrual cycle.

BBC: NEWS | Health | Woman's scent can lure or repel

The team said even though the end result was about attracting the best romantic partner available, ovulating women's choice of dress was motivated by the other women in their environment.

BBC: Ovulation hormones make women 'choose clingy clothes'

Women who were ovulating and who had seen photos of attractive local women were most likely to buy "sexier" clothes compared with those shown photographs of unattractive local women or women who lived more than 1, 000 miles (1, 600km) away.

BBC: Ovulation hormones make women 'choose clingy clothes'

Women who are starving stop ovulating.

ECONOMIST: Abolishing ageing

Two years after her wedding and still not pregnant, the 26-year-old visited a gynecologist, who diagnosed her with polycystic ovary syndrome, an endocrine disorder that can cause women to stop ovulating, gain unusual weight, develop irregular periods or skin problems and grow abnormal facial and body hair.

FORBES: Conflict Trauma in Kashmir Leads to Infertility, Miscarriages