The metaphor of a ticking clock is often used to refer to a woman’s growing urge — from puberty onwards to menopause — to conceive before her childbearing years are over. New research shows that there’s more truth to this phrase than you might think. “The very subtle sound prime of a ticking clock changed the timing with which women sought to have children and the traits they sought in potential partners — both central aspects of women’s mating-related psychology,” says one researcher.