Involved in fertilization by controlling sperm migration into oviduct. Interacts with LY6K (PubMed:24501175). Interacts with TEX101 (PubMed:23633567). Localized in round and elongating spermatids. Localized on the anterior part of the sperm head, and is removed during the acrosome reaction. Initially synthesized as a 110-kDa precursor in round spermatids, and the precursor is then processed into a 42-kDa mature protein during the sperm transport into and/or once in the epididymis. There are two genes in human, ADAM3A and ADAM3B that are non-functional (PubMed:11439107). ADAM3A gene is deleted in infertile men and in some fertile men. ADAM3B transcripts, from testicular RNA of ADAM3A-deficient men, present many stop codons in all possible reading frames. Moreover these two proteins are neither detected in extracts from the testis of a man with the ADAM3A-positive genotype, nor of a man with a ADAM3A-deficient genotype.