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Genetics and sex of babies

(14 Posts)
MoonlightMojitos Thu 20-Oct-16 22:58:18

So the general consensus with a quick Google seems to think that genetics play no part in what sex you will be more likely to have. It looks like this is based on the fact that roughly 50/50 boys to girls are born each year therefore there must be an equal chance. However, there is one article I found where they actually researched family trees of thousands of families back hundreds of years and did find a strong link between men who had more brothers than sisters being more likely to have sons and visa versa.

Just thought it would be interesting to hear your opinions on if boys or girls appear to run in your family or not and if you think it's coincidence or genetics smile

NameChange30 Thu 20-Oct-16 23:02:53

As far as evolution goes, it would make no sense whatsoever for there to be a genetic tendency towards one sex or another - we need a roughly equal balance to continue the human race!

I think it's just chance as to whether a sperm with an X or Y chromosome meets the egg first.

Miloarmadillo1 Thu 20-Oct-16 23:03:38

It is slightly biased by status and occupation. Men with higher social status and with more stereotypically 'male' brains have slightly more sons than daughters. www.psychologytoday.com/articles/200909/the-scientific-fundamentalist-chip-the-best-block

Cupcakesarah Thu 20-Oct-16 23:05:29

Well the male gamete (sperm) contains either an x (makes female) or y ( makes male) chromosome, so genetically it is 50% but I could understand that if some men's sperm, the ones with x were more viable, or the Ines with y were better swimmers etc... this would lead to higher incidences of boys/girls in family, but I've not done any research into it... PubMed is a good place to start looking for papers...

NameChange30 Thu 20-Oct-16 23:09:43

Milo Interesting article, thanks for sharing! I'm torn between shock and hmm, not sure how robust the research is but some thought provoking arguments to consider.

MoonlightMojitos Thu 20-Oct-16 23:10:02

namechange but... if an equal amount of men were more biased to boys as were to to girls then it would still even out overall?!

cupcake that's what I'm thinking, some men may just have more x or y sperm or like you say healthier ones of one or the other.

milo that's interesting!

Annabrooke90 Fri 21-Oct-16 12:04:01

I'm not sure but my children's dad has a very male run family. His dad had 11 siblings. Out of the 12 only two were girls, and then his dad and mum went on to have four boys his brother has a boy and me and him have four boys smile

chloechloe Fri 21-Oct-16 12:32:03

I've also read that men who come from a family of brothers are statistically more likely to have sons but am not sure if there is any science to explain why.

In my husband's family it is the case. He is one of two brothers and his brother had two boys. Both their cousins are also male and each had sons. So over 2 generations there were 8 consecutive boys. The 9th, 10th and 11th were finally girls. No. 10 is our DD and no. 11 is DD2 due in December!

fuzzywuzzy Fri 21-Oct-16 13:03:54

I used to work with a guy from a family of all boys, they had a large family and all that generation were boys, all the brothers and cousins went on to have only girls, when colleagues wife was pregnant I asked if he was having a boy or girl he said girl, he didn't have to ask the sonographer he knew it would be a girl. And he was right.

My cousins are mostly boys and they've all had mostly girls.

It's all anecdotal would be interesting to see a proper survey.

nennyrainbow Fri 21-Oct-16 13:22:34

For most people, the chances are roughly 50:50 but I do think some people have higher odds of one gender ( usually boys) through genetics. My neighbour was one of 7 boys, no girls, and I have know of another large family with only one daughter and lots of sons.

Environment is also said to play a part. Generally being in good health is said to predispose you to have sons, whereas less healthy people have a very slightly higher ( probably <1% difference) tendency to have daughters. This could have an evolutionary explanation, in that, if conditions are hard, it is easier to continue the human race by having daughters than sons ( one male can fertilise several females at the same time so males are more dispensable as you don't need so many). There have been studies that linked wealth with a higher proportion of male children.

GiGiraffe Fri 21-Oct-16 13:58:40

DH's father had a son and a daughter, his father had 4 sons and no daughters

My dad was one of 7 brothers and I sister - there is just my brother and I

We have 2 daughters

Don't know what this means anecdotally smile

Nikki2ol6 Fri 21-Oct-16 15:31:01

My partner is one of two. He has a sister, we are expecting boy number 3 and at my gender scan I said to the lady we really want a girl and she says I'm sorry it's a boy!! She then went on to tell us we probs won't ever have a girl..... I asked why? She says if this is boy number 3 it looks highly likely my partner has a lot of boy swimmers. I don't know if it's true or not but I guess she sees it every day

Lizb1990 Fri 21-Oct-16 16:12:19

my granny has 2 girls, my mum has 2 girls and Im currently cooking a little girl smile convinced Im going to have another girl next time! grin

Honeybee79 Fri 21-Oct-16 16:33:08

Anecdotal evidence only here and I remember at the time thinking it was v odd. My DH works at an all girls' school. The staff body is also overwhelmingly female. For the last 7 years, no teacher employed by the school or spouse of any teacher has given birth to a girl. There have been numerous births - in excess of 25. Not a single girl. The theory is that in such a female environment, there is a greater probability of boy children. I have no idea if there is any sound science at all behind that, but it is v odd.

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