clarification to my above post: I was answering the question literally and not necessarily in context. The reasons I wouldn’t want my seminary/Beis Medrash children doing the above are: 1. I wouldn’t want them online in the first place, and 2. I wouldn’t want them having online discussions with strangers.
I think the gender of the strangers would bother me way less than the fact that they are online and that they are having discussions with strangers. In terms of the gender, it would depend on many factors.