Methods of reducing fertility include
A. Confining intercourse to the period from the 10–20th day of the menstrual cycle.
B. Bilateral ligation and division of the uterine tubes.
C. Bilateral ligation and division of the vas deferens.
D. The use of agents which prevent the fertilized ovum from implanting.
E. Mechanical barriers (condoms and caps) which are the most effective methods.