CATSPER2 (cation channel, sperm-associated 2): CATSPER2 is vital for sperm motility and fertility, as it forms part of the calcium channel complex in sperm required for the hyperactivated motility essential for fertilisation. Mutations in CATSPER2 can result in male infertility due to impaired sperm function. Research into CATSPER2 offers insights into reproductive health and potential targets for contraception or infertility treatment.