User blog comment:EliteHawks123/Space Marines(not the game..)/@comment-4206721-20110812115432

Space marines, undergo a rather hefty ammount of surgery to such an extent that they are not realy human anymore. They are pumped full of combat drugs by their armour and implant glands including human-fatal levels of steroids. Ever wonder why there are no women? Well, even if a chapter recruited a female, she would undergo a hormone-based sex change purely from the ungodly testorerone levels in her system. Second, this steroids overload kills their lobedo and makes them sterile. So, no kids, no sex drive.