Why few People has Six Fingers ?

Abhinav asked me a Question while driving. " Why few people has Six Fingers ?" it was his second comment about Six fingers.( first one link - Click here)

Source: Google Image

I told him that " it is due to growth of additional finger while they are inside in their mothers stomach". I did not tell that it is mutation , genetic issue  and polydactyly because he is still very small to digest such a complex terms. (me too !!!) . I thought i answered him upto his expectations.

Again he asked me " Why it is growing?"

So i extended my explanation such as " if any one parent has the same issue, then baby also can get one". 

Source: Google Image

Again he asked me " How it is possible for baby inside mothers stomach if his Father has six fingers?".

I started blinking. He was right on point to understand the connection between baby and father. But it is too early to educate him about it. So I told him that's Nature.

PS: Me and Priya wondered and "how Children can think out of box thinking and ask always relevant questions ?"