It's not about a harem, it's about having a legion of kids before the apocalypse he's trying to start, and also probably to colonize Mars. He's insane.
"Space flights are merely an escape, a fleeing away from oneself, because it is easier to go to Mars or to the moon than it is to penetrate one's own being."
Oh, I fucking HOPE so! The thought of all those assholes dying horribly of radiation and/or starvation on the trip or on Mars proper just fills me with joy.