GEAM can perform ovarian transplants to rescue lines of mutant or transgenic mice that have difficulties breeding or have never generated offspring. Donor mutant/transgenic females are moved to the quarantine room at Biotechnology Center. GEAM will excise the ovaries and transfer them into two recipient ovariectomized wild-type females (one per recipient). Recipient females must be strain histocompatible with the donor. Recipients are housed at GEAM for two weeks to assure recovery from the surgery then transferred to the investigator for breeding.