The present invention relates to two primordial germ cell-specific expressed genes, Fragilis and Stella. The sequences and sues of human Stella and Fragilis are disclosed herein, as are several mouse sequences related to Fragilis. The present invention relates to the use of Stella and Fragilis as markers for primordial germ cells and can be used to identify such cells. Additionally, the present invention relates to the use of Stella and Fragilis for the diagnosis, treatment and/or prevention of disease.