Female fertility is determined by the number and quality of oocytes which are set at birth.听 Our dtudies aim (1) to identify the cause and mechanism of the major oocyte loss in fetal and neonatal听 life, and (2) to delinate the influence of early meiotic events on the competence of oocytes for fertilization and embryonic development.

The sex of an individual is determined by the combination of sex chromosomes, XX or XY, in mammals. Once the gonadal sex is established, however, most of sex characteristics are determined by the hormones produced by the gonad regardless of the chromosomal sex. Exception is the germ line; proper set of sex chromosomes maximizes the fertility of each sex. We are particularly interested in the role of sex chromosomes in female germ cell differentiation, in addition to the mechanism of gonadal sex determination.