being jewish is a religion, not a nationality/ethnicity.
you might as well ask if republicans are big.
That's not completely true, is it ?
I think there has at least been an influence of the religion on the bloodlines; for example, you can't really just "convert" to Judaism, as I understand it ? There are ( and have been ) rules about marriage etc. - this may well have influenced the genetic lines. Isn't that one way they have done work to trace past migrations into eastern Africa, Europe etc. ?
I'm not sure if the issue about penis size is really true though. I've seen a few examples of the opposite effect, but I guess I don't have a statistically valid sample :redface: