Some causative factors Antioxidant deficiency Lack of fresh fruit and vegetables Mutations. Down's syndrome would disappear if it were not constantly renewed by new mutations.
Older women are likely to have been exposed to more mutagens than younger.
The case for preconception care of men and women , page 20. AB Academic Publishers, Bicester, UK 1991. Adapted from the Nutritional Health Bible by Linda Lazarides. If you use this search facility regularly, you may prefer to buy this book.