**2.8 Identifying genes that increase sensitivity to reproductive toxicants**

Genetic factors that elevate risk for disease can be grouped into two categories: those for which having a particular allele conveys a high risk for the disease regardless of other (e.g., environmental) influences and those associated with only small increases in risk of the disease. The latter, termed susceptibility genes are being identified at an increasing rate. The interaction of these alleles with environmental agents or other susceptibility alleles ultimately determines whether the disease will be manifested. Much work has been done to understand the role of these genes for reproductive toxicity.
