OBJECTIVE: The purpose of this study was to assess the effect of interleukin (IL)-13 deficiency on fertility and reproductive performance of adult mice and on morphological and behavioral development of the offspring. METHODS: Wild-type and homozygous IL-13-deficient (KO) mice were grouped by genotype, and male and female mice were mated within each group. Adult (F(0) ) mice were evaluated for reproductive performance, and development was assessed in F(1) fetuses on gestation day 18, and in F(1) pups to postnatal day 35. RESULTS: In F(0) males, there were no differences in the number of males that mated or impregnated females, or in total sperm count or sperm motility, between the wild-type and KO groups. In F(0) females, there were no observed genotype-related differences in fertility, length of gestation, number of viable fetuses per litter, or viability of offspring. There were no differences in embryo-fetal development (external/palate, skeletal, visceral) of the F(1) fetuses between genotypes. Similarly, IL-13 deficiency had no impact on any postnatal parameters assessed including reflex, sexual maturation, learning, and memory. CONCLUSIONS: IL-13 deficiency had no observed effect on reproductive performance or morphological and behavioral development in mice.