The left hand doesn't know what the right hand is doing

I have been wondering about Miss O's handedness for a while now.
Will she be the dominant right hander, or will she be the alternative left hander.

The reason for this musing? Observation, of course.

Since her ability to use her arms and hands has become more obvious, she has appeared to develop skills dominantly on one side, then transferred that interest to the other side. I can't say that I have noticed which side starts this off, but I can say that it appears to change focus regularly.

Currently she appears to be mainly ambidextrous with a leaning to the left side. She does things with both hands, but is favouring her left for the fine pincer movements and the throwing of objects. And a fine throwing arm she has too. Just ask the larger of our fur children about bouncing plastic rattles hitting him between the eyes from a great distance.

What I would like to know about handedness is this:-

- is this laid down in the brain prior to birth?
- is it hereditary, like blue eyes that pop up from brown-eyed parents?
- when does this facet settle down and become 'dominant'?

Or, does this develop as the child uses and learns their motor skills?

If there is any wise soul out there who knows the answers, or can point me at some information, the unenlightened would like to know.

Just for the record, both Mr O and I are right-handed.
However, my paternal grandfather wrote right-handed but used his tools left-handed. I have little doubt that he was left-handed but of a generation (b.1913) when children were forced to write by the right. And my cousin, like our grandfather, is also left-handed.

This is just another wonderful aspect of our little Miss that she is slowly letting us get to know. Ah, joy !