Hoshizora no Babylon -Semarikuru Cosmic Sukebe Onee-sans-

In the cosmic year 2068, men are a rare commodity, and Galaxy Amanogawa finds himself the target of the Cosmic Race—humanoid space monster girls emerging from a wormhole. They seek to mate with human males for reproduction. With the ship's captain and a bevy of heroines by his side, Galaxy fends off their advances, but his value as a scarce male makes him a perpetual target, leading to relentless attacks and thrilling challenges.