Fertility is impaired in Ropn1GT and AspGT/Ropn1GT mice, but not AspGT mice. Motility of sperm from wild type, AspGT, Ropn1GT, or AspGT/Ropn1GT mice was assessed by trained observers. To determine fertility, male mice were housed with wild type female mice for a minimum of 5 weeks. N=10 for each line, ± indicates standard error.