Hmm let's think the use-cases:
- Males, any preference: 100% of singles and 33% of non-singles (if it's anonymous enough) would have the "male seeking sex with [preference]" flag on all the time.
- Females, homosexual: 100% of singles and 33% of non-singles (if it's anonymous enough) would have the "female seeking sex with female" flag on all the time.
- Females, heterosexual: 1% would have the "female seeking sex with [random]" flag on, and 99% of those by accident/joke by their friends, as they know that 100% of single and 33% non-single man they see wouldn't mind having sex with them anyway.

Seriously (if that was not serious enough), go ahead, but might be a good idea to make it a bit more general like adding choices like "going to a movie", "taking a beer" etc, so the original wish would be just one choice.