Tidy UpEdit

I am going to tidy up and edit this section as part of my revision, see also Twin. Mostly Zen 14:08, 12 June 2006 (UTC)

This section needs to include:

Monozygotic Dizygotic

Monochorionic Dichorionic

Offspring of Monozygotic twins heritability

Heritability of various conditions, e.g. Schizophrenia, Depression, bipolar, intelligence (vs environmental influence), personality?, other conditions such as Autism etc...