Making contraceptives and abortion available only encourages teenagers to have sex. Teenage sex has complex societal causes. Reality dictates that birth control and abortion be available to help prevent teenagers from becoming parents. Adoption is a better alternative to abortion. A woman should be able to decide for herself.
Some women do choose adoption, but many more choose single parenthood.
Adoption is a difficult route for anyone to take, and it is not fair to demand that women carry a pregnancy for 9 months and then give away a baby. Many women feel they could not do this and no one has the right to force a woman to do so. For a married woman, giving a baby up for adoption is virtually impossible legally. The revelations in recent years about the abuse of children in institutions and the 'export' of unwanted babies to America in the past has turned many people against adoption. Abortion is being used as a method of population control in underdeveloped nations.