I don't think the OP overreacted at all.
I don't think that discussing the potential consequences of a chemical (which may or may not include birth defects in unborn fetuses) is bad per se. BUT I totally disagree with singling out a person by name, like the OP's boss did.
Imagine if one of the men at the meeting was known for "enjoying several drinks at work Happy Hour every Friday". Imagine if the boss had said at the meeting, "The more I think about it, the more I feel Jack shouldn't be working with this chemical, as it may cause further damage to his liver". Chances are, there'd be an uproar over boss's bad etiquette.
To the OP - I'd keep my eyes open about this one. Bring it up with your boss in private if you want, and make sure the boss doesn't hold you back from any plum projects, etc by virtue of the fact you are a female.