"EWWW it sounds like a lady part! What an awful, disgusting name!". Some of you guys are really acting like 10 year olds learning about the birds and the bees about this. It's not an English name, not every name can sound good in every language. It's not a big deal. No one is telling anyone to name their kid this nowadays. And also, the female anatomy is not a "hideous" association, as some have put it. Anyways, just because it's not acceptable in your timeline in your part of the world doesn't mean that's the case for everyone, so don't be dramatic.
Yeah the name is a bit bad in English. But two things to remember. Not every country speaks English, duh, and in some countries, this has no other meaning. Second, at the peak of this name's popularity, Hyman would have not been widely known by the general populace as a term for a part of the vagina.
Does he have sisters named Virginia and Chastity? I know that this is just a name information site and that nobody is encouraging names... but did people know what a hymen was back in the day? And I hope that he doesn't provoke any fights, otherwise someone will try to "pop" Hyman.
Many Russian (possibly other nationalities as well) Jews named Chaim (or Chayim or any of the other variations) immigrating to English-speaking countries changed their name to Chyman, thinking that that was how their name would be construed there, or that it would help them assimilate because of other names ending in -man. This is what my great-grandfather did when he came to England.