"Is birth control really a bad idea?"
An anonymous blogger has asked, "Is birth control really a bad idea? Not everyone can afford raising a lot of kids". Thanks, Anon, for your question which I assume pertains to the use of artificial contraceptives by married couples. There are many factors involved - moral, spiritual, physical, personal, and psychological - that make birth control a bad idea for couples. God understands that 'not everyone can afford raising a lot of kids', and has given couples a natural way to do family planning.
Artificial contraceptives were invented by man, and are against God's Plan for couples. God's Plan for couples is that "the two of them become one body" and that they "be fertile and multiply" (Gen 2:24; 1:28). Contraception interferes with both of those parts of His Plan because it prevents the union between husband and wife and blocks any chance of procreation. The word contraception (which literally means "against the beginning of life") shows us that it is opposed to God because God is life, and contraception is anti-life.
We have seen the use of contraception grow exponentially in the past forty or fifty years, especially in the U.S. It is no coincidence that while the use of artificial contraception has become widespread, so also has divorce, adultery, abortion, fornication, murder, pornography, domestic violence, etc. risen dramatically. This was predicted by Pope Paul VI in Humanae Vitae in 1968. He predicted that at least two things would happen if contraception became widespread: 1)that there would be a vast moral decline in society, and 2)that men would treat women with much less respect and objectify them. He is a prophet on both accounts, unfortunately.
Physically, birth control pills can be very harmful to a woman's body, whether she knows it or not; please check out the article* from the web site below which has more information. Personally, the couple that contracepts communicates less and prays together less than couples who don't, on average as shown by statistics. These same statistics show that the overwhelming majority of couples who get divorced used contraception. Finally, the psychological approach of "I want this (sex) but I don't want that (kids)" is very damaging: it basically says 'I can get what I want with no consequences'. This is one of the reasons why there has been such a moral decline in our society since contraception became widespread.
God has given to couples a natural way to plan as parents. It's called Natural Family Planning (NFP), and it is very easy to use. People in third-world countries have had much success in learning to use it effectively. The couple who has discerned in prayer and in their own conversations that God is not calling them at that time to have a child abstains from sex during the fertile part of a woman's cycle, which is only about 3-4 days out of the month. NFP allows for an openness to God's Plan which contraception does not. God does not will every couple to have several babies, but He does call each of them to be open to life in a pure, natural, and loving way.
* "Contraception: Why Not?" by Dr. Janet Smith, 1994.