A mother's womb has a reputation as a snuggly place for a foetus to chill out whilst its developing, but it's a reputation that is definitely undeserved. The womb is a baby killer. Carrying a baby to full term is a lot of effort, not to mention the risky business of then delivering said bonny babe. It makes sense, therefore, that the mother would not want to risk investing her time and resources into a sub-par foetus. Not every fertilised egg will turn into a strong, viable foetus, and so the womb essentially sets up a kind of endometrial Hunger Games to sort the men from the boys (so to speak). The endometrium, that supposedly cosy womb lining, is extra thick in humans to prevent the placenta from latching onto the mother's blood supply for as long as possible. This is so that she has as plenty of time to decide whether she's going to bother with this one. In fact, scientists have found that the single most difficult place to get an embryo to take hold in the bodies of mice, is the endometrium. If the embryo is rejected, the lining sloughs off and this is one of the reason why humans are some oft he only mammals that menstruate. So, that fact that you are reading this means that you are one of the very few embryos that passed the test and were allowed a pass by your mother's womb. Impressive stuff, but maybe don't include it in your next Mother's Day card. Want to write for What Culture Science? Click here to find out how you could get paid to write about what you love.Does science make you tingle in your brain box? Like us on Facebook or follow us on Twitter for more.
