A. A. Haspe/s It is with pleasure that I welcome you, on behalf of Professor Rolland and myself, to Amsterdam for this International Symposium on ''Benefits and Risks of Hormonal Contraception''. As a means offamily planning the pill is about 25 years old - a timespan which has been characterized by an enormous increase in public interest and concern with family health and family-planning. Undoubtedly we have learned a lot over the last 25 years. As you see in Figure 1, in the seventies in Holland relatively more fertile women used the pill than in any other country in the world. In 1974 new combination pills were introduced containing less than 50 JAg of ethinyl estradiol. In 1981 50 % of Dutch pill­ users took a sub-50 (Figure 2). The same is true for the Scandi­ navian countries. In our own University Clinic 95 % of pill-users take a sub-50 pill; only 5 % use a 50 JAg pill on medical indication. This decrease in estrogen dosage, which is usually accompanied by a decrease of progestational component as well, has resulted in a decrease of thromboembolic disease. Factors that are still important to consider are diabetes mellitus, hypertension, adipositas and smoking. Good selection of patients together with the prescribing where possible of sub-50 pills may result in the numbers of compli­ cations and side-effects being close to those encountered in the control group.