Compounds suitable for use in providing male contraception, an assay method for identifying such compounds, and methods of providing contraception using the compounds, are provided. In one embodiment, the compounds described herein mimic the binding of anti-EPPIN antibodies to EPPIN, and thus inhibit the forward motility of sperm in humans and other primates. In another embodiment, the compounds described herein inhibit or enhance EPPIN-semenogelin binding, and inhibit forward motility of sperm. The assays described herein identify compounds which inhibit sperm motility, and can be carried out in a high throughput manner, using labeled recombinant EPPIN and semenogelin. The compounds can be used in oral or transdermal compositions to temporarily and reversibly inhibit male fertility. They can also be used in addition to, or in place of, spermicides in spermicidal compositions, such as those used in conjunction with condoms, diaphragms, and spermicidal jellies.