CS Lewis on Contraception

"(A)s regards contraceptives, there is a paradoxical, negative sense in which all possible future generations are the patients or subjects of a power wielded by those already alive. By contraception simply, they are denied existance; by contraception used as a means of selective breeding, they are, without their concuring voice, made to be what one generation, for its own reasons, may chose to prefer. From this point of view, what we call Man's power over Nature turns out to be a power by some men over other men with Nature as its instrument."

The Abolition of Man 1947 (Taken from the 1973 paperback edition by the Macmillan Company, pp68-69)