As a matter of fact, it does affect your fertility - specifically, it gives you a percentage chance equal to your virility (i.e. 100% virility gives a 1% chance; this also caps at 5%) of impregnating Ellie without having to give her a fertility treatment, and gives you an effective +300% virility to attempts to knock her up if you have given her that treatment. Outside of that, you're no more or less likely to conceive children than any other Steele.