If that were the case, then the curse wombs created by Kenjaku in Kano Noritoshi’s body would just be regular fetuses, not curse wombs. The wording implies that Noritoshi’s body was the one to impregnate her after her initial cursed pregnancy. This is further reinforced by the fact that 1-3 have use blood manipulation techniques. Since Gojo’s six eyes can’t discriminate Goto from Kenkaku, he likely uses the hosts own cursed energy. So he probably doesn’t pass on his own genes, or his own cursed energy, but he may have somehow imbued the wombs with cursed energy during insemination to make them ultra-cursed — this only possible because of the woman’s ability to give birth to curses.

So his superhuman strength may have been passed down from either his father or mother, or a combination of the two. We have to assume that conniving little Kenjaku brought those particular people together for a reason.