It is possible that you may not have been aware that any ethical questions existed concerning contraception. The contraceptive methods that involve the changing of the lining of the uterus to prevent implantation from occurring create an ethical or moral consideration for some people.
Some people believe that life begins at conception whereas others believe it begins at implantation. The ethical consideration develops for individuals who believe that life begins at conception.
When contraceptive methods fail to prevent ovulation or fertilization, the changing of the uterine lining is used to prevent the fertilized egg or “life” from implanting in the uterine wall. It is this action that leaves people believing they have crossed an ethical boundary.