Would a child of a hermaphrodite have two Y chromosomes?
February 5, 2007 7:28 AM   Subscribe

Is it possible for a hermaphrodite to conceive a baby with a man, and the child to end up with two Y chromosomes?

Would a hermaphrodite who chose to be female still have Y chromosomes floating around? Would she actually be able to have a baby? What would the theoretical double Y child look like?
posted by Suparnova to Science & Nature (15 answers total) 5 users marked this as a favorite
I'm pretty sure the human body is not designed to carry a child like that to term.
posted by AthenaPolias at 7:37 AM on February 5, 2007

YY alone would be a fatal combination. You need at least one X to make a viable embryo. There are some individuals with XYY sex chromosomes, but not (as far as I know) born with one male and one hermaphrodite) parents.
posted by roofus at 7:44 AM on February 5, 2007

They've done it in tilapia, but as roofus says a YY embryo wouldn't be viable. Most of our genetic information is on the X chromosome, as the link says.
posted by winna at 7:50 AM on February 5, 2007

I think it depends on whether the hermaphrodite is kitted out with a womb but from what I can find it's pretty unlikely. I suggest you ask an OBGYN
posted by parmanparman at 7:50 AM on February 5, 2007

Full agreement with roofus: YY is not be viable.
posted by mcstayinskool at 7:54 AM on February 5, 2007


Searching the NIH website found lots of articles showing that true hermaphrodites can have children who do not bear signs of hermophrodism.
posted by parmanparman at 7:54 AM on February 5, 2007

Slightly off-topic, but on the XYY thing...interestingly, there is a hugely disproportionate percentage of male prison inmates with XYY as compared to the general population. Turns out that extra Y makes you a meanie. Go figure.
posted by mcstayinskool at 7:57 AM on February 5, 2007

Sexing the Body by Anne Fausto-Sterling, and the Intersex Society of North America are good places to start if you are interested in learning about the kind of genetic variation that we end up classifying as male and female. There's a lot.
posted by carmen at 8:16 AM on February 5, 2007

Turns out that extra Y makes you a meanie.
Or just dumb enough to get caught.
posted by monkeymadness at 8:16 AM on February 5, 2007

mcstayinskool: do you have a cite for that? I've heard about it in the past but nothing authoritative.
posted by edgeways at 9:20 AM on February 5, 2007

do you have a cite for that?

Alien 3
posted by nanojath at 10:08 AM on February 5, 2007

edgeways, the wikipedia article has 5 different footnotes after the words 'Aggression is not seen more frequently in 47,XYY males.' dunno if it's an urban legend or what, but it looks to be fairly clearly debunked.
posted by sergeant sandwich at 11:21 AM on February 5, 2007

Human chromosomes are not organized the way a competent engineer would organize them. Since genetic information is located by searching for specific header sequences, it means that related genes are not required to be physically near one another on the same chromosome. And in practice, they're scattered hell-and-gone all over the place.

So though the X-chromosome is one of the "sex" chromosomes, it isn't the case that it only contains information relating to sex dimorphism. In fact, it carries all kinds of critical stuff -- and one of the reasons that boy babies have a higher infant mortality rate is because they only get one genetic chance for all those genes to get it right.

That's why virtually all hemophiliacs are male. The gene in question on the X chromosome encodes for one of the enzymes in the clotting cascade, and if your one-and-only copy of it is busted, then you get to suffer from hemophilia. For a girl to suffer from it, her father has to be hemophiliac and her mother has to be a carrier. (And given that until very recently it was nearly certain that boy hemophiliacs didn't survive to manhood, that was very unusual.)

No one really knows for sure just what genetic information is involved (unless there have been some recent breakthroughs I haven't heard of) but almost all type-I diabetics are boys, because the gene involved is on the X chromosome. (Again, as modern medicine has massively improved survival rates for diabetic boys, the number of daughters suffering from it has begun to rise slightly.)

And there's lots of other critical stuff on it -- which means that without an X chromosome, a zygote isn't viable. I'm not sure how many cell-divisions it would manage after fertilization before it failed and died, but I doubt it would be many. There's no way it would survive long enough to implant in the uterus.

(Here's a list of X-linked genetic diseases. Most of them are recessive in girls, but in boys effectively they're dominant. The point of the list is to show that the X-chromosome carries a lot of important information about critical systems that have nothing whatever to do with sex.)
posted by Steven C. Den Beste at 1:15 PM on February 5, 2007 [1 favorite]

A lot of the urban-mythiness around the XYY thing must have come from this TV series of the 70s.
posted by AmbroseChapel at 3:18 PM on February 5, 2007

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