Hermaphrodites!

The odds that a pregnancy will result in the birth of a Hermaphrodite are approximately 1 in 250,000 (0.0004%)

Now, I'm not gonna go out on a limb and say that Lady Gaga is a Hermaphrodite, thats for you, and bookies, and her traumatized boyfriend to discuss. Not that I'm above that or anything, I just prefer dealing with facts and quantifiable data...With that said, Lady Gaga is mentally retarded. And the creative director for The Muppets dresses her.

(This number may be off, my figure is from the NIH and cited in this book - http://www.amazon.com/Odds-R-Roger-Schlaifer/dp/0553383469, most internet answers seemed far too high)