Ethan of Athos

1986 novel by Lois McMaster Bujold.

Summary

Dr. Ethan Urquhart, obstetrician on Athos, a men-only world, must leave his planet to find new ovarian cultures to ensure his people's survival.

During his stay at a nearby space station, he encounters Elli Quinn, a mercenary on a secret mission, and both of them become embroiled in dangerous matters of espionage and bioengineering.