This gene is a member of the kernel lipocalin superfamily whose members share relatively low sequence similarity but have highly conserved exon/intron structure and three-dimensional protein folding. Most lipocalins are clustered on the long arm of chromosome 9. The encoded glycoprotein has been previously referred to as pregnancy-associated endometrial alpha-2-globulin, placental protein 14, and glycodelin, but has been officially named progestagen-associated endometrial protein. Three distinct forms, with identical protein backbones but different glycosylation profiles, are found in amniotic fluid, follicular fluid and seminal plasma of the reproductive system.