It does NOT mean you will pop out of the womb as a Satanist.
It does NOT mean you will be born with some esoteric knowledge of Satanism
It simply means that those born "carrying the gene" for Satanism
will be better able to display those attributes that one might expect of a Satanist. . .
. . .It's that simple. Think of it as having the gene for red hair. Genetically, you can get red hair if the factors fall into place. This does not mean you will HAVE to be born with red hair. It simply means you are genetically predisposed to that trait.
If you are genetically predisposed to those traits one might expect in a Satanist, you MAY develop them, if other factors fall into place. That does not mean you HAVE to become a Satanist, or that you automatically will think of yourself as a Satanist. It simply means that your are genetically predisposed to that trait.