The same reasons that we love soy may also be the reasons that a diet rich in soy may be of concern. Soy contains "phytoestrogens", plant compounds that mimic the female hormone, estrogen. This is great when you are post-menopausal woman and needing a little extra estrogen to combat those hot flashes and other side effects of menopause. But some researchers feel that soy has the same influence on young boys and girls.
High soy intake in babies and young children may contribute to earlier menarche in girls and later fertility issues in boys. These theories have been explored in animals but not confirmed in people. There is enough evidence though for some countries such as Israel, England and New Zealand to limit the routine use of soy formula. How much soy is too much and do we want our kids to be taking in large amounts of "phyto-estrogens"?
What to do? Well, until all of the evidence is in, it may be better to think before you drink.
Small amounts of soy milk are fine, but consider the other dairy alternatives such as nut milks or hemp milk. If your baby shows an allergy to dairy based formula, soy might not be your best choice, talk to your doctor about an elemental formula.