Based on data provided anonymously by 2,611 women and 1,452 men using a computerized questionnaire, we found that 19.2% of women vs. 16% of men (p <.001) were aware of being attracted to people with physical characteristics resembling members of their nuclear families, a phenomenon called sexual imprinting. Women reported sexual imprinting on fathers (15.5%), brothers (2.5%), mothers (0.8%), and sisters (0.4%), and men reported sexual imprinting on mothers (11.5%), sisters (2.1%), fathers (1.9%), and brothers (0.5%). The likelihood of women imprinting on fathers increased when fathers were more affectionate to them and when parents were more affectionate to each other. The likelihood of women imprinting on brothers increased when they had an older brother. The likelihood of women imprinting on mothers increased when parents divorced or separated and there was a remarriage. The likelihood of men imprinting on mothers increased when mothers had a positive attitude about sex. It decreased if they had an older brother and increased if they had been the victim of child sexual abuse (CSA) by an adult female. The likelihood of men imprinting on sisters was increased if parents were affectionate to each other. Three factors predicted the likelihood of men imprinting on fathers.