A sperm donor will usually donate sperm to a sperm bank under a contract, which typically specifies the period during which the donor will be required to produce sperm, which generally ranges from 6â24 months depending on the number of pregnancies which the sperm bank intends to produce from the donor.perm donation is the provision (or donation) by a male (known as a sperm donor) of his sperm (known as donor sperm), principally for the purpose of inseminating a female who is not his sexual partner.