In her first few months, your baby cries incessantly in the wee hours of the night, quashing any plans you might have had for love making. Is she just hungry or could this bundle of joy be blocking your joy for another reason?
A recent Harvard University study suggests that babies cry to keep their mom exhausted and to keep her from ovulating. If she can keep her parents from having sex, that will delay the arrival of a sibling who would compete for food and affection.
"I'm just suggesting that offspring have evolved to use waking up mothers and suckling more intensely to delay the birth of another sibling," Harvard researcher David Haig told an NPR health blog.
Haig, an evolutionary biologist, published his interesting findings in the current issue of the journal Evolution, Medicine and Public Health. Other researchers weighed in on the subject.