Methods for Prenatal Sex Determination and Their Importance in Understanding and Prevention of Gender-Related Birth Defects

Abstract

Various hormones, chemicals, and teratogenic agents exhibit gender-related effects in utero as well as postnatally. Among such gender-specific teratogens are endocrine disruptors, especially phthalates that affect male gonads, diabetes-induced oxidative stress with more deleterious effects on male offspring, procar-bazine-induced cleft palate affecting more male fetal rats compared to females, and VPA-induced autism-like behavior that affects differently males than females. Hence, there are many needs for the accurate determination of genetic gender. In newborn animals, the morphological methods that exist for sex determination (i.e., anogenital distance) are generally inaccurate. Hence, an accurate and simple method for the prenatal and early postnatal assessment of the genetic sex, prior to reliable evaluation from the external genitalia, is of utmost importance. Indeed, several methods have been developed for accurate assessment of genetic sex, which are discussed in this chapter. Findings from studies in our laboratory have shown that the method described by McFarlan et al. for the assessment of genetic sex in adult mice by PCR of Sly/Xlr genes can be reliably used for the genetic sex determination of any tissue, including embryos and fetuses, with an accuracy of about 100%.