First, REGARDLESS of the truth or fiction of the Roman-Italian association...
To call ANY race a "weak mutant offspring" is not only a bigoted comment in its nature and general meaning, but especially in a world filled with "ethnic clensings" in the last century... those are not acceptable words or terms for any race and are offensive (and this is coming from the Jew who eats ham regularly, questions God, and generally calls anyone who does not scrutinize ideas or beliefs before accepting them foolish... and then some... I'm not at ALL Mr. PC, I LOVE to stir the drink, so to speak, but there's stirring it and then there's spitting in it...)
In regards to the question... I don't think the Romans were native to the Penninsula, the earliest peoples came and settled there when the Italian tribes were already there... there IS some historic truth behind the Iliad, and the Aneid is the Roman follow up, so perhaps they mingled with the Italians after coming to Italy from... Troy, perhaps? If we take the texts (that aspect of it, anyway, concerning the Greeks fighting a people called the Trojans for whatever reason, Troy destroyed, and then a diaspora... it's happened before AND "Trojan" and "Roman" are not too dissimilar... perhaps...?)