Many animal species have a behavior in which females avoid male relatives when they are fertile . . . this seems to be nature’s way of avoiding inbreeding . . . well, it’s easy to observe the behavior in animals but what about more social diverse and advanced animal species like humans, the ol’ naked apes? Researchers noted how much time a group of young fertile women spent on their cellphones with their fathers and mothers by keeping track of cellphone records. They actually did find that over all, the young women talked to their fathers much less while they were the most fertile. They found that they called their fathers much less when fertile and that even if their fathers called them they talked with them for much less time. See http://pss.sagepub.com/content/early/2010/11/24/0956797610390385 for more on this fascinating bit of evolutionary biology.

– Brian