Exposure to stressors during particular stages of development leads to acute and long-term physiological and behavioral changes. We have reported that shipping mice during the peripubertal/adolescent period results in decreased induction of feminine sexual behavior by estradiol and progesterone in adult female mice. To study further the factors involved in this decreased behavioral response, female mice were exposed to a variety of experimental stressors when 6 wk old. Effects of peripubertal/adolescent exposure to these stressors on acute plasma corticosterone levels and changes in body weight and adult behavioral response to estradiol and progesterone were assessed. Although restraint for three daily 3-h periods, 36-h food deprivation, or a multiple stressor regimen acutely increased plasma corticosterone levels and reduced body weight, only exposure to particular doses of the bacterial endotoxin lipopolysaccharide (LPS; 1-1.5 mg/kg body weight, doses that induced moderate levels of sickness behavior in these studies) resulted in reduced behavioral response to estradiol and progesterone in adulthood. Like the effects of shipping, the effects of LPS on adult feminine sexual behavior appear most robust when injected at 6 wk old and are limited to exposure during a vulnerable period at approximately 4-6 wk of age. Therefore, an immune stressor during the peripubertal/adolescent period, but not restraint, food restriction, or a combined stressor, has an enduring influence on behavioral response to estradiol and progesterone. This demonstrates that the decreased response to estradiol and progesterone is not a general response to all stressors during this developmental stage.