I suppose it makes sense but it's not quite logical..
In biology when a mother and father reproduce there are ways to predict what traits the child will inherit. (Punnett Square)
Say the Father (madara) has Ab for eyes being the sharingan path and the mother being aB for eyes (senju) the capital letters would be the dominant trait and the lower case, the recessive trait. just for the purpose of this example say the SO6P had AB pattern for eyes. The odds of the child having AB from Ab and aB is 1/4, the odds don't reduce each time they reproduce, they stay the same. So logically it's possible, but highly improbable...
if you search "what happened to nagato's parents" in google it'll come up with a naruto wikia with information that states both of nagato's parents were killed by leaf ninja while fighting them to allow nagato to escape (it was shown in the anime)
I believe that rules out any possibility of nagato being madara's son
also go to chapter 517 page 11 the second box shows nagato as a child with a scar under his eye on his cheek, i suppose this suggests that the eyes were surgically planted...time we look for another solution lol
Yes, i have a degree in health and i took a genetics class. But for example, there are traits that only manifest when two different informations are present. For example, in certain animals lets say the mother is AA for black fur and the father BB for blond fur. The child AB has the manifestation of both and the fur manifests as brown. And even so, 25% of chance isn't that bad. Also, there's a place in the manga that sugests that nagato was adopted. Why? first because he was an uzmaki and his "parents" weren't. They hadn't any of the traits. I'll go look for the manga chapter of that to confirm.
Also, that boy in chapter 507 is the former mizukage, the tree tails jinchuriki controlled by madara. It's not nagato. Llol