A genetic component exists for most forms of human disease, including many different abnormalities affecting pubertal development and fertility in men and women. This study is interested in identifying causative gene mutations in several different reproductive disorders including delayed puberty due to gonadal failure and idiopathic hypogonadotropic hypogonadism, premature ovarian failure, recurrent abortion, ovulation disorders, and male factor infertility. These disorders represent a continuum from a severe to milder phenotype (from delayed puberty to premature gonadal failure to infertility). This study will test candidate genes for linkage and linkage disequilibrium, and perform mutation screening of putative disease genes. This study will also enroll unaffected controls, particularly unaffected family members, which are necessary for linkage analysis. Through these efforts, we hope to identify genetic causes of delayed puberty and infertility. If mutations are identified, we will assess their effect in vitro, if possible.