Ethan of Athos by Lois McMaster Bujold
Synopsis from GoodReads
The familiar old SF “planet of women” chestnut is reversed in the planet of Athos — an all-male planet made possible by the invention of the uterine replicator. Ethan, drawn out of his beloved Athos by a quest, finds himself an alien in more mainstream human society, and cannot help but find women disturbing aliens as well, especially the ultra-competent, ultra-beautiful Elli.
Ethan of Athos is Lois McMaster Bujold’s third novel. It departs from the concerns of the Vorkosigan family to explore the ramifications of advanced biotechnology, turning many a cliché on its head along the way.