Blogging from A to Z Challenge. For those unfamiliar with the concept, it's basically about 26 posts (we don't post Sundays), preferably on a theme, blogging our way through the alphabet from A to Z. My theme this year is all about TV Tropes, celebrating random tropes with some sort of weird, odd, unusual, controversial, or taboo element that appeals to my warped sense of literary adventure.
Continuing the theme, we have Male-to-Female Universal Adaptor (check out the page for a complete definition, but your first guess is probably pretty close to the mark). After a quick perusal of the Literature examples provided, I've gotta go with:
"SF author John Varley absolutely loves this trope. The Gaea Trilogy has the Titanides, an alien species who are sexually compatible with humans because they were deliberately engineered to be sexually compatible with humans. Steel Beach has the ULTRA tingle system, which gets around the whole genital compatibility issue entirely by using wireless modems for sex. Finally, the novel The Ophiuchi Hotline has literal male to female universal adaptors that allow characters who go in for radically modified genitals to "dally" with their more conservative counterparts."