probability of having twins?

[newbroom]

I'm hoping some of you knowledgeable people will be able to answer this as I've googled and am still confused! We are hoping to have a second baby at some stage but DH is convinced we will end up with twins... obviously we would be delighted although it would be a bit of a squeeze ...

Anyway, please can anyone tell me if my family history means I'm any more likely to have fraternal twins? (I understand that identical twins are pretty much random). In my family, there are no twins in mine or my parents' generation. However, my paternal grandfather and his brother were fraternal twins, and so were my maternal great uncle and great aunt (not my grandmother though). I read that twins can skip a generation but surely not two? (No twins in DH's family btw).

If anyone can help I would be very grateful

i think that it has to pass down the maternal line??? but i might be making that up entirely

I think that the "twins skip a generation" thing is a myth.

It does come from the maternal side, but that just means it comes from you and your ancesters and it's nothing to do with your DH's (the paternal) side of the family. It could come from your father though, (or grandmother etc) as that's probably where it came from with me. My GreatGrandmother had 9 pregnancies but 12 children (3 sets of twins all fraternal). One of the twins was my grandmother. She then had my dad and aunt (both singletons) and my dad has me, and I have twins.

It's probably not easy to explain (or more I'm not very good at explaining it) but women have two XX chromosomes and men have XY. To have a baby girl you get one X from the mother and one from the father, to have a baby boy, you get the X from the mother and the Y from the father. If my great grandmother carried the twin gene on one of her X chromosomes (hence she was XX) then my grandmother could have been XX or XX (a 50/50 chance of inheriting the X from her own mother. So she had my dad, and if she was XX (50/50 chance)he would be XY or XY. So again 50/50 chance. He then had me, and as men dictate the sex of the child by giving the Xor Y I would have to inherit his X. Which would either be X or X depending on how it went earlier on with my granny etc.

Anyway, I had fraternal twins, which mean I must be XX, so working back my father must have been XY and my granny must have been XX.

So it could have happened that the twin gene had gone from the family, and I thought it had, but suddenly it pops up again in me. Some of my dad's cousins are twins, and some of his singleton cousins have gone on to have twins too. And also, just because you carry the twin gene doesn't mean you will always have twins. Great Granny had 6 single children as well as the 3 sets of twins. And my granny must have carried the gene for me to have got it, but she never had twins.

Furthermore I suspect I've oversimplified it, as genes can be dominant or resessive as well, so it's probably a lot more complicated.

Also it could be that I've not have twins due to genetics, it might just have been one of those things. As you get older you are more likely to release 2 eggs, and also if you have had a lot of children previously you are also likely to release more eggs, so higher chances of twins.

So in answer to your question, you might have twins. . Sorry, I know this doesn't put it in hard numbers for you! But twins are lovely, so don't worry about it, and if you want more children, just go for it.

(Sorry for stupidly long, and probably confusing post)

Actually looking at it on a bit of paper - for your case the twin gene will have been lost from you paternal grandfather. He would have been XY or XY having inherited his X from his mum. But regardless of which he was, he would have gone on and given his Y to your dad, so the twin gene would have been lost from that line.

Your Grandmother might carry the X as her mother must have had it to have had your twin great aunt and uncle. So there is a 50/50 chance your granny had it, and a subsequent 50/50 chance that your mother inheritited it from her, and then another 50/50 chance that you got it from her. So 1/8 chance you MIGHT have the twin gene???

Sorry, I'm bored and work and find genetics fascinating!

Love that explanation GG - fascinating stuff!

Thanks everyone, that's interesting and reassuring! Might be able to report back in a few months time

There isn't actually a twin gene at all

There is a propensity for some women to ovulate more than one egg at a time and this can be inherited from either your father or your mother.

So my DP, who is a twin, can pass his mother's tendency to ovulate more than one egg, on to our daughter (but obviously it doesn't affect our sons directly)

The reason why the twin thing is said to skip a generation is that if you are a twin and you have a son, they aren't more likely to have twins (because it's actually only WOMEN who have twins) but if you are a twin and you have a daughter, she might have twins.

The son of a twin can pass the tendency on to his daughter, that's the thing to remember

I seem to remember from when we were TTC, and having problems, that the consultant said there was a 1:82 chance of having twins normally/naturally and 1:10 with clomid. (DH and I are the latter - the doc was trying to warn us! And I still didn't think it would happen to us )