Twins?!?!

[tqueensberry]

So, come to find out twins run on my mother's and father's side. I feel like I'm kinda large to only be 14 weeks. I've read that sometimes a second baby/heartbeat can be missed at early appointments. I had my first ultrasound at 8 weeks and only one baby. At 12 weeks my midwife checked the heartbeat, only one heartbeat. Is it possible there is a

Comments

[thiscantbesoy]

in families where the women have a gene for hyperovulation, genetics would sufficiently explain an increased presence of fraternal twins.

However, only women ovulate. So the connection is only valid on the mother's side of the family. While men can carry the gene and pass it on to their daughters, a family history of twins doesn't make them any more likely to have twins themselves.

Fraternal twins "run in families" on the mother's side only, if she inherits the gene for hyper ovulation.

Google brings up many more sources explaining this.

http://www.twinsarefun.com/2009/06/what-are-the-odds-of-having-twins-if-twins-run-in-your-family/

http://www.chacha.com/question/do-twins-run-on-the-mothers-side-or-the-fathers-side

http://multiples.about.com/b/2009/07/10/forum-friday-are-twins-hereditary.htm

etc.

[ophelia42]

Yes. Your second link said what I said. "While men can carry the gene and pass it on to their daughters, a family history of twins doesn't make them any more likely to have twins themselves."

"Your dad's side doesn't affect you at all" isn't true. The father of the (suspected, potential) twins doesn't affect anything. The father of the mother of the (suspected, potential) twins can.

[thiscantbesoy]

You're reading that wrong, and you're also not reading the rest of the quote or the other sources.

[ophelia42]

No, I'm definitely not.

The tendency to have twins only "runs" through the mother OF THE TWINS side. HER tendency to have twins can come from her mother OR father.

[tqueensberry]

Okay so my BABY'S FATHER'S genes don't affect the chances of twins but MY FATHERS genes do (this would make more sense and I'm not sure about my husband's family history) ?

[ophelia42]

Exactly.

[tqueensberry]

Okay, think I got it. I know twins are on MY mother's and MY father's side, not sure whether fraternal or identical though.

[thiscantbesoy]

No. Neither does. Only the blood-relative women in your family affect it.

[meeksnmeebs]

Ok, woman is pregnant. Woman's mate does not affect whether or not she has twins. Woman's mother OR father could potentially pass along genes along X chromosome that could cause woman to experience hyperovulation. THUS, woman's father CAN affect whether or not she is genetically predisposed to have fraternal twins. If father's mother had fraternal twins, then woman is more likely to have fraternal twins.

[nickelshoe]

But I'm still blood-related to my paternal grandmother. The only way I can easily imagine that it would be strictly maternal would be if it were passed through mitochondrial DNA rather than nuclear DNA. Even if it were on the X chromosome, all XX people get one of those X's from their biological father.

I'm pretty sure the point in the sources you mention (read them all) is that the baby's father doesn't affect whether or not it is a twin, since fraternal twins are due to ovulation tendencies in the mother. The baby isn't ovulating, so it's DNA isn't the issue, just the mother's. I don't suppose this is a big deal, but I think people are right to correct your interpretation here.

[a_tergo_lupi]

Women have two X chromosomes, including one from their fathers. The baby's father does not affect twinning, but the mother's father does.

[tqueensberry]

I'll read some of these links. Genetics are complicated. I'll be sure to post after my next ultrasound appointment. Hoping for only one baby.