Researchers conducted a prospective study of men and women asking for sterilization in the Aberdeen City District in Scotland from 1978-1981. They randomly chose and interviewed 84 men and their wives and 167 women and 123 of their husbands to determine what factors played a role in their decision for sterilization. About 50% of all couples had sisters who had experienced sterilization and 20% had brothers who did. Therefore sibling experience played a significant role in the couples' choice between male and female sterilization (p.05). Spouses of only 19% of all couples were both willing to be sterilized. 66% of the wives in the vasectomy sample and 50% of those in female sample wanted to stop using oral contraception. 46% of the couples in the vasectomy group reported that both spouses were willing to be sterilized. In fact, 48.7% carefully considered their decision after becoming well informed of their options and going to the physician together. 46.1% of the husbands volunteered for a vasectomy because of the shorter waiting list (p.001). The remaining couples chose vasectomy because the wives had done their share and/or concern for the wives' health, the wives did not want to be sterilized (time for husbands to assume the responsibility), or female sterilization was contraindicated. The leading reason for female sterilization was that husbands (49%) did not want a vasectomy, mainly because they would lose their manhood or it would affect their sec life. The next reason was women (23%) wanted optimal personal security against pregnancy. The remaining reasons for female sterilization included vasectomy was unnatural and medical considerations (e.g., repeated cesarean section). 5% of the couples who wanted female sterilization switched to vasectomy because of the long waiting list.