Autosomal dominant disorders are characterised by ________.
1) skipping generations if not fully penetrant
2) being inherited by equal numbers of males and females but having more severe symptoms in males
3) homozygotes always expressing more severe symptoms than heterozygous
4) On average half of the children will have blood group A
5) On average half of the children will have blood group AB
6) All of the children must be Rh positive