The "yins reproducing by mitosis" meme is funny and all until you remember that Saikhara's description was the exact same as nezha (and both super similar to Venka who minister sring thought of marrying off to the yins)
It's less "strong genes" and more imperial Chinese beauty standards being super important for the more auspicious houses, thus naturally somewhat strict physical requirements of entering the family. Remember the matchmaker scene in mulan? Yeah











