???When we look at environmental exposure, we need to think in terms of precaution,??? says Mark Roth, a teratogen information specialist with the Pregnancy Risk Network in Binghamton, N.Y. (A ???teratogen??? is an agent, such as drugs, medications, or other chemicals, that is able to disrupt or cause birth defects to an embryo or fetus.) It???s difficult to get specific data for salons, says Roth