Athos
A planet with an exclusively male population with is somewhat isolated and remote within the wormhole nexus. The homeworld of Dr. Ethan Urquhart in the novel Ethan of Athos. The population is maintained by obtaining ova from imported human ovaries, combining them with the father's semen, and incubating the resulting fetus in a the ubiquitous "uterine replicator" which appears throughout the stories. Naturally only male babies are born. It is the reception of a shipment of bad ovaries that sends Ethan off-planet to find what happened to the proper shipment, and into the center of a plot involving Barrayaran and Cetagandan agents.
Most of the men form permanent or semi-permanent relationships to help in raising children, whose birth must be approved by local committees. Some men (who, it is implied, are strongly heterosexual) cannot enter into such relationships. They variously become "confirmed bachelors", monks of a sort, or simply leave the planet. The planet is named for the Mount Athos in Greece, which is home to monasteries where no women are allowed.
Read more about this topic: List Of Vorkosigan Saga Planets