What a heated discussion! The was similar topic few years ago:
with no satisfying resolution.
Speaking of 金玉, while learning this item few weeks ago, I checked Tofugu article
and they have this passage:
It’s worth mentioning here Japanese culture is a lot less uptight about this sort of body-part humor than the West.
I guess that was in the past, and modern Japanese are as uptight about the basic anatomy as Westerners.