The RCC should encourage its faithful to use birth control, the world is overpopulated.
As I understand it, the RCC position on birth control comes from Thomas Aquinas' consideration of the Natural Law of Aristotle. Aristotle believed that the primary purpose of sexual intercourse in human beings is reproduction.
It may well be that while the primary
biological purpose of sex is reproduction, sex has a more important
survival role - that of strengthening the bond between couples. Since human offspring take a very long time to mature, a strong bond between the parents offers the possibility of continued protection during maturation. It could also be argued that reduced fertility (in the form of fewer children) also provides greater protection to existing children making it more likely that they will achieve maturity.
I think that by recognising that its view on birth control comes not from any biblical source but from ancient Greek philosophy, the RCC might find it relatively easy to change its stance. Most adherents in first world countries appear to ignore RCC teaching on this matter anyway.