Songfacts®:

• "Procreation (Of the Wicked)" is the third track on the European release of Morbid Tales, but the fifth on the US release. It is written by Tom Warrior and Martin Ain.
• Other groups to cover this song include Sepultra and Enslaved. Tom Warrior, while expressing dislike for most covers of Celtic Frost songs, has said that he liked Sepultra's cover, saying "They play it note-by-note, which I generally don't like, but they made it theirs by putting in an aggression that we didn't possess at the time." Since then, he's considered this song as the benchmark for how good Celtic Frost would be if there were a reunion.
• In the book Precious Metal: Decibel Presents the Stories Behind 25 Extreme Metal Masterpieces, Martin Ain says of this song: "'Procreation' has such an organic feel to it; it's genuinely heavy and primitive. It was sort of like if Robert Johnson lived in our time and played heavy metal, this is what he would've come up with. It just seems really timeless, and I also like the lyrics. I think they're some of the best lyrics we've written."
• Horst Müller did back up vocals on "Procreation (Of the Wicked)," also on "Dethroned Emperor," as well as producing the album. At the time of working with Müller, session drummer Stephen Priestly hadn't even known that Müller had been a much bigger star in the '60s and '70s. While Warrior and Ain had kind of over-ridden Müller on production while working in their previous band Hellhammer, they realized that they were better off listening to his ideas this time around.