"I see a slippery slope." Then don't step on it. The balance of your comment already is swaying a little.
Feminist cousines would not be offended when called cousine.Yes, cousinette would be a little over the top. They would really be offended however if you would call them guy, boy or fellow.But I won't take this case to the judge, don't you worry. (as long as you introduce your waste papers politely)