"Contraception is another issue where pro-life goals of protecting the unborn and fostering a culture of life seem to contradict one another. If sexually active individuals used birth control more often, there would likely be fewer unwanted pregnancies. However, easier access to contraceptives might encourage even more sexual activity among unmarried people. This is especially the case if contraceptives are made available to populations which include a high percentage of sexually inactive people, such as young teens. It would send powerful messages about the sort of sexual behavior that is both expected and acceptable.
"The increase in sexual activity among teens during the 1960s provides good evidence of this. The birth-control pill was first approved by the FDA in early 1961 and put on the market later that same year. A study by the Alan Guttmacher Institute (hardly a pro-life outfit) found that women who turned 15 between the mid-1960s and early 1970s were more likely to engage in sexual activity at a younger age than their counterparts who turned 15 between the mid-1950s and early 1960s. Furthermore, the Guttmacher study partly attributes this increased sexual activity to the availability of the birth-control pill. The widespread use of birth control in the 1960s seems to have shifted the culture in such a way as to hasten rather than delay the liberalization of America’s abortion laws.
"So when the pro-life movement faces a situation where protecting the unborn and building a culture of life are at odds with one another, most pro-lifers resolve the tradeoff in favor of a culture of life. This seems prudent for a couple reasons. First, a high percentage of abortions are performed on unmarried women. As such, the best strategy for reducing abortion is to reduce the incidence of premarital sex. More importantly, it will be difficult for the pro-life movement to make substantial legislative progress in a sexually promiscuous culture. As such, the pro-life movement must succeed in building and strengthening a culture of life before it will be successful in restoring legal protection to the unborn."
— Michael J. New,—"Contraception Conundrum," National Review Online. Read the whole article.