We have found that, in terms of sexual development, there is very little difference between children who, as infants, were fed cow milk formula and those fed soy formula, said Brian L. Strom, MD, MPH, director of the Penn Department of Biostatistics and Epidemiology. The biggest concern has been whether or not phytoestrogens in soy had a feminizing effect on children.
Strom is quick to add, however, that the idea is not entirely unfounded. Phytoestrogens, which occur naturally in soy, are analogous to the human female hormone estrogen. Infants fed soy formula receive relatively high doses of phytoestrogen during a time of life when they are rapidly growing. It comes as no surprise, then, that the possibility of altering a childs development had concerned some parents and scientists.
In this study, we interviewed young adults who had been part of feeding studies as infants, said Strom. We were looking for abnormalities in their adolescent and sexual development attributable to their early exposure to soy phytoestrogens.
This study has its roots in a landmark study at the University of Iowa, which first started looking at the effects of soy formula on infants beginning in 1965 and lasting until 1978. At the time, soy was still relatively new to the American diet. Then, as now, soy was seen as an excellent source of
Contact: Greg Lester
University of Pennsylvania School of Medicine