While fetal ovarian germ cell number is unaffected by vitamin A deficiency, the germ cells in embryos with the most severe vitamin A deficiency fail to enter meiosis as evidenced by a lack of immunostaining for SYCP3 (a gene that encodes a component of the synaptonemal complex), and the critical RA-responsive gene, Stra8 is nearly undetectable. The gene discussed is SYCP3; the disease is vitamin A deficiency.