(NSFW) What genetic variations or disorders have you encountered in the opposite sex that turns/turned you on more than you expected.

So last night, I had my first experience with a female with inverted nipples. I am not a whore but I have been with women who have unique skills but for some reason this genetic variation turned me on more that anything else I have ever, experienced. what genetic disorders or variations have you found to be a huge turn on, that you didn't expect?