I over heard a conversation at the zoo today between a set of twins parents and some random person
random person: So are they Identical? (they were Boy/Girl)
Dad: Yes in every way except one has a penis.
Random person: Oh I didn't realize they were boy girl. I've never heard of identical boy girl twins.
Mom: Oh no, the egg split before it was fertilized
I always thought it was impossible for that to happen? and wouldn't the egg splitting first and getting hit with different sperm, mean they WEREN'T identical?
I kind of side eyed the whole convo because then the random guy started asking if they were "natural"
Re: Twin ? Is this possible???
Well at first I was going to say they were kidding b/c we tend to say the same thing about ours- um well one has a penis & one doesn't...
but the egg split before it was fertilized? wth? first of all eggs don't split & even if it did, that means it was fertilized by TWO different sperm which would not = identical. (like you said)
No, b/g twins cannot ever be identical, as they are different genetically by at least one chromosome (and likely quite a few more, like any other siblings, obviously).
This. If we ever had boy/girl twins and were asked that I would most certainly give a response along those lines.
I thought so too, until the mom actually started off on the whole egg splitting before being fertilized thing.
The babies were bundled up in the stroller so you couldn't "really" tell that they weren't boy/boy or girl/girl twins one had a purple hat and the other a brown hat.
The only reason I know is because I grew up with b/g twin friends that were constantly asked if they were identical. They looked NOTHING alike. So it was funny, but thats the only reason I knew about it.
People just don't understand what identical is. I have a twin brother, he is 6'2", I am 5ft. We both get asked all the time if we are identical and people will straight up ask when my birthday is turn and then ask him.
It is possible for an egg to fertilized by two sperm and split so they would have "identical" in the sense that they are getting the same genes from mom but different from dad... I didn't think it was possible until I did a lot of research after discovering I was going to have twins (and they talk about it briefly in the National Geographic documentary "In the Womb: Multiples"
While it may have been a smart@ss comment from the parents... it is possible
  
It's amazing how many people don't get what "identical" means. My twins are the same sex but one has light blond hair and the other has dark brown hair (and different faces, somewhat different eye color, etc.) and people will also ask if they are identical. I just don't get it because I knew the difference between identical and fraternal twins when I was 7 or 8. :P
I've heard this before too. When I was in school, they said there's no way this could happen (15 years ago). I heard about the above about a year or so ago. It's VERY rare to happen and I think in those cases the children are infertile (I could be wrong).
I also vote smartass. I typically respond with "No, the boy has a penis." Not necessarily nice but when I'm trying to grocery shop with all 3 kids and am stopped every 3 minutes or every other aisle to discuss my fertility, how my hands or full or the status of my twins, that seems to end the conversation succinctly. I think in that case, they have found that using the word penis usually ends the conversation. And if it doesn't, throwing scientific jargon out will!
And it is possible, but is the result of a genetic mutation- I think in .01% of b/g sets and results in a developmental disorder...I think it's turner's, where the y chromosome is missing or absent or something like that. there are other explanations, but I'm not sure what they are.
If someone is asking that when they can't tell (like in this case) that one is a boy and one is a girl, fair enough. But when they *know* that one is a boy and one is a girl and still ask if they are identical, I'm sorry but that really is a silly question coming from anyone over the age of 12!
Or like in my case. Even at a glance, it should be pretty obvious that my boys aren't "identical."
 (And I do also get strangers saying, "But they can't be twins! They don't look alike!" As well as every once in a while the, "Oh, are they identical?" question still.)