There is no evidence at all that soy formulas are less allergenic than
cow milk based formulas.  Furthermore, in addition to the phthalates
which may interfere with sexual development, soy formulas have a very
high aluminum content.  In addition, they have not been around as long
or used as much and not been studied much (like all formulas), so that
their safety is less certain than cow milk formula.  They also smell
awful and taste awful.  Finally, they are generally thicker and pass
through lactation aid tubes less well.  And it goes without saying
that they are associated with at least all the risks that cow milk
formula is associated with.

In Toronto, soy formula is used a lot by the orthodox Jewish
community.  I cannot imagine what the attraction is.

Jack Newman, MD, FRCPC