Genetics & baby’s sex/weight

[bookwitch13]

Hi everyone!

I was just interested to know your thoughts on whether the weight or sex of the baby is determined by genetics (by this I mean it follows the father’s side for example)

The reason why I ask and am curious- my husband’s side of the family give birth predominantly to males. My husband is one of 3 boys as is his dad. My husband’s brother recently had a baby which also turned out to be a boy.
My mother in law refuses to acknowledge the possibility of me having a girl, to the point of it not even being discussed as a potential. Do you think that genetically, I am more likely to have a boy?
(Obviously not looking for definitive answers, I am just curious!)

The same goes with weight. My MIL’s sons were all over 10 pounds, and my recent nephew from husband’s side weighed 11 pounds 3 oz when he was born. Of course, to my MIL this now means inevitably I am going to have a large baby eye roll which sometimes isn’t the most reassuring of thoughts so early on.

Any thoughts on this? Anyone else been involved in similar conversations with their families and did you manage to grin and bear it?! Haha!

Thanks in advance x

I'm sure there's a genetic link between the size of the baby and the size of its parents at birth, but why is MIL so sure it will come from the father's side of the family? If you were a small baby this baby might take after you!

Not sure about sex. It's basically 50/50 each time but I think there is some evidence to show that some women only give birth to boys?

@Orangebug if I knew how and why my MIL thinks certain things, I would be a psychic genius!

I think the reasoning behind the weight theory is that husband’s father was also a larger baby. I’m purely just interested to see if it’s happened to anyone else!

There are no definite answers here :) just curiosity. I don’t even put too much thought into skull and nub theories. So this is purely for my own musings!

In my fathers family , his father had several boys and one girl, each of my fathers brothers have been the same one girl and several boys. It hasnt followed through to my cousins though. So I've often wondered is it genetics or just coincidence? On My partners fathers side of the family it's mainly boys as well and from what I can remeber it's the sperm which decides the sex of the baby.

@romdowa yes I’ve seen about sperm determining the sex of the baby! Which leads me to thinking if males have a similar amount of X and Y sperms which would make it reallt a 50/50 chance or more of one or the other which would alter it!

It’s so interesting to me! And I’m unsure of any scientists really truly know the answers yet!

[quote bookwitch13]@romdowa yes I’ve seen about sperm determining the sex of the baby! Which leads me to thinking if males have a similar amount of X and Y sperms which would make it reallt a 50/50 chance or more of one or the other which would alter it!

It’s so interesting to me! And I’m unsure of any scientists really truly know the answers yet![/quote]
there is so much they dont know about the human body and why things happen. Genetics is an absolutely fascinating field and I'm insanley jealous of anyone who can actually comprehend it 🙈🙈

yes I’ve seen about sperm determining the sex of the baby!

Do you mean this is a new and exciting concept to you? It’s not a new finding.

Yes, genetics are a thing. Yea, your baby may well be influenced by genetics on your DH side. They may be influenced by genetics on your side. Or a combo. It’s complicated. Not really sure what you are asking here though?

In our case, DH comes from a male-heavy family whereas mine is female-heavy. DH was the smallest of his siblings at 8lbs 7oz. I was 6lbs at birth. We've had 2 boys and both were 8lbs 7oz! So very much have taken after DH's side of the family here.

I think I read sometimes that some men only produce male/female sperm so that could explain the preference for one sex. However, mostly its 50/50.

Birth weight can often be linked to parents birth weights, but doesn't tend to run in families. Its so hard to predict birth weights and lots of other factors are at play too.

@HoppingPavlova

yes I’ve seen about sperm determining the sex of the baby!

Do you mean this is a new and exciting concept to you? It’s not a new finding.

Yes, genetics are a thing. Yea, your baby may well be influenced by genetics on your DH side. They may be influenced by genetics on your side. Or a combo. It’s complicated. Not really sure what you are asking here though?

Excuse me? No it is not a new and exciting concept to me, there is no need to be so rude - though I’m not surprised at there is at least one unnecessarily aggressive post on each thread on here.

It’s clear what I’m asking if you read my posts, I’m looking to see if people have experienced patterns with sex of baby or weight. It’s not difficult to understand and I don’t know why you’re confused about what I’m asking?

Can I Suggest you go and find some other posts to chat on? I was looking for interesting conversation around this topic, not be made to feel like an idiot.

For the record; not everyone is obviously as clued up on genetics as you appear to be. This could be a good opportunity for people to learn.

I know a family (paternal line) in which there hadn’t been a girl born for more than 100yrs. Then one girl came along!
So exceptions do happen even in long established patterns.

There are theories that some men’s boy sperm can be compromised by severe illness or early trauma.

Our family of 3 generations tend to produce small babies. None over 6.5lbs. I was the lightest at 3.?lbs (i was very premature though). My mums side mainly girls but my uncles side mainly boys 🤷🏻‍♀️

I do think there's a genetic link.
My dad was born at 10lb as was most of his brothers.

My DS was 10lb 1oz at 39 weeks. I'm 5ft 5 and only gained 2st the entire pregnancy. DH is 5ft 8 and he was born 6lb.

I was born 3lb 3 at 9 weeks early.

Guessing I just carry big babies

The birth weight is linked to the maternal line - so if you were a big baby, then yours might be too. Father doesn't play into it. If I remember correctly it's down to pelvis shape etc that means you get a baby to match ;)

I don’t have any experience of birth weight being genetic though. I can imagine the idea of a 10lb doesn’t fill you with confidence, good luck with that one!

Thank you to everyone participating in such an interesting conversation so far! I always find it amazing on here when people feel the need to be rude for absolutely no reason!!

@SansaClegane ahh so good to know! On my side, we are a very regular 6/7 pound bunch of babies

@ContessaVerde 😂😂😂 haha not really!! But what will be will be. I keep thinking I’ll have a record breaking 15 pounder!!

So husband was nearly 10lb at birth. My first was 8lb at 41wks and second was 6lb10 when born at 37+5. Not huge babies.

My husband has one sister. His dad had 1 brother not sure about grandpa.

We have 2 girls and his sister has 2 girls.

Also my dh is 6ft4 and I'm 5ft1. I assumed I would have tall children but they are small for their age and slim like me. Look more like dad though, damn!

My dad was 1 of 3 boys and his brother ms all had only boys but he had 2 girls 🤷🏻‍♀️

@miliie55 thanks for sharing! My sister’s husband was from or family of mainly boys and they went on to have 2 girls! Which makes me come back over to the “randomly determined” train of thought!

I have 5 boys and the full term ones were all born the same length and weight give or take an oz or 2. The premature babies were both born on the same centile as their brothers and when they got to their due dates they were the same length and weight as their brothers were at birth. All other babies in the family were a variety of weights and a mixture of both sexes so not sure about genetics but I think I just grow babies that size.

@elliejjtiny thanks for sharing! so interesting that your body just knows the right size of your baby for your body! And 5 boys is amazing 😍

We don’t have any boys on my side of the family, and no girls on husbands. I’m absolutely made up to be pregnant after miscarriage and am over the moon to have one or the other :)

Oh,that's interesting,never gave it much thought but now makes me think a bit more about my family.
My paternal side MY DF one of 3 boys,my DF had 2 girls,1DB G/B,2nd DB boy
My maternal side MY DGran 3G/1B, she had 4sisters/2brothers,my DGF had 1 sis,she had 2 girls
MY DM 2girls,Sis1 1boy,Sis2 G/B,her DB 2boys
MY husbands side
He was the only grandson,had sister and 3 female cousins
Now,I had 3DS and DD.
When it comes to weight,my DCs were bang on average,mean weight was 7,7lb while me/DSis were significantly lighter and my exH was above 9lb.
All in all,yes genetics do play a role but it's not set in stone,your MIL is mad (and sincere sympathies,my MIL was like this,will do/say anything to upset me,be on top etc)

@3JsMa thank you! And yes she is mad haha 😂😂 we suspected it would be like this even pre pregnancy! It will be an interesting few months to navigate through that’s for sure!

@bookwitch13
Pleasure,I totally understand and speaking from experience I wish I was less scared and trying really hard to be kind and respectful.
Be firm,be diplomatic and most of all,DO NOT BE SCARED to voice your opinion and stick to your guns.There is nothing that will stop these women to make you feel inferior.The best line at the moment would be ''You had your children,now it's my time to enjoy motherhood''
Good luck OP,enjoy your pregnancy,such an exciting time

Of course there are links but your genetics will have a big impact too. Until you have had your 1st you can never know what you will get.

Our 1st was a very average 7lb 7oz (39+6), 2nd 10lb 12oz (40+5), 3rd 9lb 10oz (40+2), 4th&5th twins 8lb 5oz & 8lb 11oz (38). We were not big babies, I was 7lb 5oz and hubby was smaller as he was a premmie (his mother always changes the weight and gestation). I'm 5ft 8 and he is a little over 5ft 9. I had a lot more stress in my 1st pregnancy than the others, I had a few bouts of high blood pressure (was induced because of it) and I don't think my diet was as good back then either. 24+4 atm and think this one will probably be another big one as bump is growing super fast, they haven't booked me any extra scans as they think I'll be fine given how I coped with the others.

Every woman in my mums side of the family for generations has had a girl first. There are boys but more girls and first born is always a girl. I find that strange!