from this site:
http://www.biotech-info.net/soya.html
I'm pregnant. Should I avoid soya?
Probably, and especially if you're vegetarian. A new study of babies born to vegetarian mothers showed that baby boys had a five-fold risk of hypospadias, a birth defect of the penis. The researchers suggest this was due to greater exposure to phytoestrogen rich-foods, especially soya. Inappropriate hormone levels such as that caused by a high intake of soya during the first 12 weeks of pregnancy can also cause damage to the foetus's developing brain.
But surely I can feed my baby soya formula? It must be safe: it's available in every supermarket and chemist.
Soya-fed babies are taking part in 'a large, uncontrolled and basically unmonitored human infant experiment', said Daniel Sheehan, director of the FDA's National Center for Toxicological Research, in 1998. A newborn baby's sole food is the milk it drinks: a soya-fed baby receives the equivalent of five birth control pills' worth of oestrogen every day, according to Mike Fitzpatrick. These babies' isoflavone levels were found to be from 13,000 to 22,000 times higher than in non-soya fed infants.
As a result of this phytoestrogen overload, soya-fed babies have a two-fold risk of developing thyroid abnormalities including goitre and auto-immune thyroiditis. Boys risk retarded physical maturation, while girls risk early puberty (1 per cent of girls now show signs of puberty, such as breast development or pubic hair, before the age of three) and fertility. Researchers have also suggested that diabetes, changes in the central nervous system, extreme emotional behaviour, asthma, immune system problems, pituitary insufficiency and IBS may be caused by high phytoestrogen intake in early life. Last year, compounds in soya were also implicated in the development of infantile leukaemia. Current government advice is that breast is best and that soya formula should not be given to infants unless on the advice of a health professional.