Brothers and Periods

Hmmm, this is a strange one...

It's been known for a while that girls from families with absent fathers begin periods earlier than those whose fathers are present before and around puberty, but Australian researchers have discovered that having older brothers delays the onset of a girl's menstrual period. Dr.Deborah Judge and Phd student Fritha Milne, from the University of Western Australia recently released the relevent study in Proceedings of the Royal Society (Biological Sciences)

According to Judge "What we found was that there was an older age at menarche [when a girl first gets her period] for girls who had older brothers,". However it's not clear why this should be occurring.

The study reveals that the greater the number of older brothers, the later the occurance of menarche. Girls with older brothers and no sisters started menstruating art 13.6 years. Girls who had no older brothers or sisters or only older sisters began menstruating at 12.7 years, while girls who had both older brothers and sisters began menstruationg at 13.3 years.

The Western Australian research is an interesting addition to previous, related studies about reproduction and family relationships, where anthropologists have noted that in traditional societies the more brothers a family has, the fewer children their siblings have. However Judge notes that in societies where resources are more plentiful, one would expect siblings not to have this kind of effect on each other...and indeed in the Western Australian study Judge and Milne did not find that the number of brothers affected the number of children siblings had, or the age at which they had their first child.

Interestingly though, a further finding of the study revealed that girls with younger brothers started having sexual activity later than those without younger brothers. Judge posited that the impact on sexual activity could be because older girls tended to help parents look after younger children....thus older sisters are too busy looking after their younger brothers to go out and potentially explore sexual experiences.


Father Substitute...?

In order to test whether or not the latest findings were a result of brothers having a kind of *father substitute* effect, Judge and Milne checked to see if the age of the older brother had any effect on the age a girl starts her period, but found it did not.

Why older brothers should affect the age of menarche in their sisters is something of a mystery:

"We don't know what's delaying menarche.It could be a physiological effect in terms of food or some other sort of resource, but I doubt it. Or it could be some sort of psychosocial process that's slowing down the girls' maturity." Judge speculated and added " It may have something to do with hormones or the different way girls are treated when they have an older brother".

Other researchers have speculated that when the father is absent, girls menstruate earlier in order to unconsciously attract a mate to have a greater chance of securing resources but with older males in the house the biological imperative is not so great. However this would contradict Judges conclusion that in plentiful societies resources would not be an issue.

Judge was keen to emphasise that the findings do not indicate that there is any adverse effect from having later periods.

Source

Catalyst, ABC Science


Test your masculinity/femininity...check out Science Oddspot, The Finger:

http://hubpages.com/hub/The-Finger

More by this Author


Comments 22 comments

secularist10 profile image

secularist10 6 years ago from New York City

Who knew periods could be so interesting.

It does seem reasonable to think that having more "big strong males" around would allow a girl to safely continue in a relatively more juvenile state for longer. It's interesting that the difference between girls with no siblings and girls with older brothers is almost a year.

There might be another explanation: in a home where the girl is the only child, she enjoys more net resources (food and nutrition, attention from parents, etc) than in a home where she has siblings. Other studies have found that the age of puberty for girls has been declining over the years in the developed world, with one reason being superior nutrition.

So an only child girl, with more or better nutrition, may be relatively healthier and thus enter puberty earlier than the girl that must share resources with siblings.

I know the scientist in the study disagreed with that idea, but I fail to see why. It would seem to be in line with other findings.


drbj profile image

drbj 6 years ago from south Florida

Jane - As that height-challenged fellow from the long-ago TV show, "Rowan and Martin's Laugh-In" used to say: "Verrrrrry interesting."


Lemmyisgod 6 years ago

I presume the statistics were correlational? In which case...you know the rest of the methodological criticisms. Interesting read though! Lemmy


Jane Bovary profile image

Jane Bovary 6 years ago from The Fatal Shore Author

It is interesting drbj.

Lemmy, don't talk to me like I know anything about how to conduct scientific research..I don't! I'm just rehashing the news here. Anyone interested though can get hold of the study through the link.

Good points secularist. Since having a father around raises the age of menstruation..from a biological/resources pov it would seem to make sense that the older brother would act as a kind of stand-in. yet Judge dismisses this, apparently on the basis that the older brothers age didn't make a difference to the results. I don't really get that.

Thanks all for the comments.


Micky Dee profile image

Micky Dee 6 years ago

I bet some girls with lots of brothers may want to deny it as well. I have no idea. But this is interesting. Thank you Jane!


Jane Bovary profile image

Jane Bovary 6 years ago from The Fatal Shore Author

Well I've got two older brothers and I don't deny it! Thanks Micky.


kate 5 years ago

that's strange, my parents are divorced and my dad is really absent in my life, I used to visit himm on saturdays, but since I turned 11 I stoped going to his house..really don't know why. I don't have brothers either..still I was one of the last one of my class to have my period, at 14. antway my twin sister had it at 11, odd..


Jane Bovary profile image

Jane Bovary 5 years ago from The Fatal Shore Author

Hi Kate,

Well, you defy the research. I guess all this is just a generalisation so there's bound to be variations. It's interesting though that your twin started at 11.

Anyway, 14 seems like a good age to begin. A hundred years ago, the average age was 17!

Cheers


RealHousewife profile image

RealHousewife 5 years ago from St. Louis, MO

It is interesting, especially because I have 3 daughters. I should buy stock in Kotex products;). Two of mine got their periods at 11! It is terrible too because they are too young for that kind of responsibility at that age, I think. Still in elementary school and one child never lived with her dad except weekends - with the other child, her dads been here every day of her life. At least I tell him I hope she's his. (Just kidding!)


Jane Bovary profile image

Jane Bovary 5 years ago from The Fatal Shore Author

haha..they're damned expensive,those things! Still, how lovely to have three daughters. That would be fun.

It's amazing how young some girls are getting periods..I mean some do at nine! Good grief.Especially when you consider that a hundred years ago the average age was apparently around sixteen. What's going on?


RealHousewife profile image

RealHousewife 5 years ago from St. Louis, MO

I have seriously wondered that myself - because of the girls. Average age was 13 when I was a teen so why does it get younger and younger every year? When I think about Darwin - I can't help wondering if there is some reason? It's the majority of the population that seems to be changing too - not just a few cases.

The girls are a constant source of entertainment (or screaming!) LOL I had 6 young girls screaming in the house all day:). They might be my undoing!


Jane Bovary profile image

Jane Bovary 5 years ago from The Fatal Shore Author

Yes, I know what you mean. Is there some survival value in it? Actually I would have thought that if anything, periods would be coming later, since most women are now having children later, but it's the opposite.

Maybe bra's for 8 year olds aren't that whacky after all..it might come to that. Just kidding!

Lol..girls are great screamers. I have one myself..that's her in the top photo.


RealHousewife profile image

RealHousewife 5 years ago from St. Louis, MO

Aww she is beautiful Jane - and I thought she looked like your photo! I bet you do know what that's like too (the screaming;) then I run around like a chicken, "what happened? Who has lost a limb?" it's nothing they say quietly.

Hey I bet if you looked at the underwear they sell for kids now you're eyebrows would be raised. You really could make a hub out of that - sadly. Padded bras for 10 year olds. It makes you wonder what in the heck?? The little bikinis they sell for tiny girls? It should be a crime.


Jane Bovary profile image

Jane Bovary 5 years ago from The Fatal Shore Author

I know! What are they trying to do...turn them into mini-hookers? Who buys them I wonder?


RealHousewife profile image

RealHousewife 5 years ago from St. Louis, MO

Right! I get so mad when I see them. I have even seen then in Wal-Mart! I wonder what the sales are like on those - because who in their right mind would want their tiny girl to have - in effect - breasts!

You could have a really interesting hub just showing photos of the clothes they are pushing - btw who manufactures them? There's the bad guy.


Jane Bovary profile image

Jane Bovary 5 years ago from The Fatal Shore Author

Beats me RH...dress-ups are one thing, sexy underwear another!

I'd write a hub except I don't want to promote them! Maybe I will anyway though...I like the idea.


RealHousewife profile image

RealHousewife 5 years ago from St. Louis, MO

Every time I see them I think that who ever manufactured them should get some lumps on the head. So - while I would laugh just seeing the mini sexy clothes - you should totally bash and draw attention to whoever the pervert is that is designing and making them.

I think that is why I will never make money on hub Jane - I only write about things I would never want someone to buy! Lol!


Jane Bovary profile image

Jane Bovary 5 years ago from The Fatal Shore Author

Haha..ok, I'm going to do it. I just hope I don't get banned by that prude adsense for mentioning *sexy underwear*


RealHousewife profile image

RealHousewife 5 years ago from St. Louis, MO

Oh I can't wait to see how you write it! Lol - I'll be watching out for it!


Jane Bovary profile image

Jane Bovary 5 years ago from The Fatal Shore Author

Pressures on! It'll be a while..I've got a couple of other old hubs half-finished and getting moldy.


RealHousewife profile image

RealHousewife 5 years ago from St. Louis, MO

I do too! I have 3 different hubs that Im alternately working on. Take your time and next time I'm shopping I'll check the tags and email you the manufacturer.

I think my 'hubs' come out a lot better if I'm thinking about it for a while. Then I find myself noticing stuff that relates too - which makes it much easier for me to write. I still can't wait though! Lol


Jane Bovary profile image

Jane Bovary 5 years ago from The Fatal Shore Author

Thanks RH!

    Sign in or sign up and post using a HubPages Network account.

    0 of 8192 characters used
    Post Comment

    No HTML is allowed in comments, but URLs will be hyperlinked. Comments are not for promoting your articles or other sites.


    Click to Rate This Article
    working