Contraception Versus Evolution?

I just read a very interesting passage in The Abolition of Man, by C. S. Lewis. He writes, "And all long-term exercises of power, especially in breeding, must mean the power of earlier generations over later ones." - p. 56 in the paperback version published by HarperSanFrancisco ZondervanPublishingHouse. This is a very interesting statement to me.

It brought to my mind a sudden realization that there is a possible contradiction, I think, between the idea of contraception and the idea of biological evolution, Darwinian or not. For the record, I don't believe in macro-evolution at all; micro-evolution is a possibility, I suppose. I haven't examined the evidence carefully. When it comes to contraception, I believe most definitely that any abortifacient is murder, and the only defensible contraception at all is that which prevents fertilization in the first place.

Now, here is the possible contradiction: if contraception allows earlier generations to have reproductive power over later generations, and yet later generations are, by evolutionary theory, superior, then what gives? Suppose you have a couple using contraception. Thus they are attempting, at least, to decide who comes into being and who doesn't. Thus they are setting themselves up as a judge over the later generation. But if evolution is true, then the later generation would make better choices. Perhaps the earlier generation should leave as many choices as possible to the later generations.

This is most definitely a half-baked idea, written at 9:40pm on a Sunday. I'd be interested in any thoughts of my readers, however.

In Christ.