The transition to viviparity (live-bearing) from oviparity (egg-laying) requires profound morphological and physiological changes in both the mother and embryo, and these changes must be associated with significant changes in gene expression.  The Australian skinks, Lerista bougainvilli and Saiphos equalis offer rare opportunities to uncover the genetic mechanisms of viviparity because live birth evolved recently, perhaps within the past 100,000 years.  These species therefore have the potential to reveal the genetic changes associated with the evolutionary transition to viviparity “in action”.  I will present the results of a gene expression study analyzing almost all genes expressed in the uterus of both species during pregnancy and non-pregnancy.  Furthermore, I compare expression both in the embryonic and maternal membranes of the placenta of L. bougainvilli throughout multiple stages of pregnancy.  In particular, I will focus on suites of genes associated with the major physiological changes required to maintain pregnancy, including genes associated with nutrient provisioning, placental morphology, and the maternal immune system.  Finally, I will compare these genetic changes to another viviparous lizard as a starting point to assessing the convergence of gene expression mechanisms across viviparous reptiles.