Obesity and reproduction: a committee opinion

•Although obesity increases the risk of infertility, most women and men with obesity are fertile.•Obesity in women is associated with ovulatory dysfunction, reduced ovarian responsiveness to agents that induce ovulation, altered oocyte as well as endometrial function, and lower birth rates after IVF.•Women with obesity are at increased risk of developing maternal and fetal complications during pregnancy.•Men with obesity may exhibit impaired reproductive function.•Lifestyle modification and medical therapy have demonstrated effectiveness in promoting weight loss.•Bariatric surgery in women and men is a significant adjuvant to lifestyle modification and medical therapy for weight loss, but pregnancy in women should be deferred for 1 year postoperatively.•In anovulatory women with obesity, weight loss interventions improve the chance of unassisted conception.•In anovulatory women with obesity, weight loss interventions improve the ovulation rate in response to ovulation induction. However, they have not been shown to improve the LBR.•In ovulatory women with obesity, prepregnancy weight loss interventions have not been shown to improve the outcome of live birth after both non-ART therapy and IVF.•The effect of prepregnancy weight loss interventions on maternal and fetal complications is unclear.•On the basis of available evidence, there is no medical or ethical directive for adopting a society-wide BMI threshold for offering infertility treatment; rather, there is considerable evidence arguing against such a policy.•Before an IVF cycle, women with obesity should be carefully evaluated with a multidisciplinary team to determine the safety of oocyte retrieval under anesthesia, considering factors such as BMI and comorbidities.