Where is John's pearlies?

I was looking at Grace's 10 mth old photos and I realised she already has her 2 bottom pearlies when she is 10 mths old (see below for evidence)... But John still has no sign of anything!!
Grace showing off her 2 bottom pearlies @ 10 mths old

John: where is my pearlies?

Hmm... Grace seems much more chubby than John @ 10 mths old