Why do women menstruate?

[Himalaya]

freethoughtblogs.com/pharyngula/2011/12/21/why-do-women-menstruate/

... perhaps a little off topic...but since there is no mumsnet/biology topic and there has been a lot of discussion on biology on here of late, I thought some might be interested in this article on the question of why humans have periods, when most other mammals do not.

I thought it was fascinating, and had always been vaguely unsatisfied with the explanation for menstruation given in school, which doesn't really answer the question.

Basically the idea is that the build up of womb lining is not so much to make a nice 'nest' for the embryo, but pre-emptive self-defense to protect the woman from the invasive connection of the placenta, and is a consequence of the evolutionary dynamics of maternal-fetal conflict.

....there is also a punchline in the article about the politics of pro-choice/pro-life debates.

oh yes, I loved this when I read it last week - thanks for reminding me of it!

The bit about the pro-life being man-friendly and pro-choice being woman-friendly was very interesting.

Very interesting article.

However, I did think that some vocabulary choices were in appropriate. For example, it says 'the greedy embryo', which suggests a consciousness and I think plays into the hands of the anti-abortionists and their 'life begins at conception' mantra.

The Greedy Embryo would be a great title for a book.

I dunno, Alex, echoed The Selfish Gene to me and was appropriate.
Could be hijacked certainly but that goes for anything really.

Animals do have periods btw.

Humans might have more of them just because we have such a nice comfortable well fed life.

I find that artlicle a bit over emotive - images like the foetus "sinking its teeth into the uterous"

I thought it was because usually in other mammals the endometrium gets reabsorbed, but humans produce too much to do that because it is needed to produce a big foetal brain. Shrew foetus = big brain?? unlikely?

Chicken - some animals have an equivalent of a period, but it's not common enough to say "animals have periods" as if all or most of them do, and it's very little to do with having a comfortable well-fed life.

I like The Greedy Embryo and The Selfish Placenta

Whilst not wanting to start yet another pro v anti flame war, I too found the reference at the end of the article to pro being a female stand point and an anti being a male stand point very simplistic and not worthy of such an interesting and thoughtful article.

It did seem to be rather stuck-on, didn't it? The suggestion is an interesting one and is worthy of its own article, but there certainly wasn't enough in that article to merit just saying it with no further discussion.

I agree, it is a bit of a throw-away comment at the end (...and interesting, but not the main point of the post...).

I guess what he meant was something more like pro-choice position will tend to favour a woman's genetic chances to maximise her decendents while being against abortion will tend to favour a man's genetic chances to maximise his decendents.

Not that we should necessarilily 'vote with our genes', since maximising decendents maybe in your gene's best interests but not you as an individual...

I thout other mammels did have periods.