I am trying to understand the rational behind the catholic church's stance against both abortion and contraception. I understand the abortion issue from their point of view but what is their problem with preventing a sperm from fertilizing an egg? This planet already has in excess of 8 billion people and our natural resources are dwindling away. Population control would seem to be an important concern for our civilization. Abstinence is no longer a valid option in today's modern sexual culture. The policy of non-participation is not realistic in today's society.
Is the Roman Catholic church's problem with contraception grounded in their holy book? If so, what part of that text is used as a reference?