Stra8, stimulated by retinoic acid 8, is expressed in embryonic ovaries just before meiotic initiation, whereas in testis it is expressed after birth. The STRA8 gene contains 9 exons. And this gene is mapped to chromosome 7q31. Retinoic acid (RA) signaling was required for Stra8 expression, and therefore initiation of meiosis, in embryonic mouse ovaries. RA was sufficient to induce Stra8 expression in embryonic testis. Cyp26-mediated RA metabolism was responsible for delaying Stra8 expression in embryonic testis. Since RA signaling regulated Stra8 expression in both embryonic ovaries and adult testis, it was said this portion of the meiotic initiation pathway may be identical in both sexes.