Dear Jonathan,

I agree with every answer that has been posted so far.
The developmental milestones tend to confuse people.
There is an enormous variety of possibilities and a lot of children do not comply with " the rules".
The differences in surroundings, genetics, 1st, 2nd, 3rd or 4th child, care AND the babies personality all contribute to his/her moving around more and more.

As a mother of 2 boys and a PPT'er I suggest you sit back, look at your childs endevours and marvel at his way of exploring his universe. Marvel at his trying and trying again, but do not worry about how and when.

have fun

Esther de Ru