That's not the claim you were making earlier. (Although, strictly-speaking, it's still wrong: many factors other than genetics are involved in producing a newborn infant, famously epigenetics. If you classify these all as "genetic factors", then yes, the claim is tautologically true by way of redefining words.)

I'd be interested to see how you'd go about controlling for those other things: so far, I haven't seen anyone manage it.