Thank you for living up to your screen name by verbalizing the ultimate in self-destructive philosophies. Children, who needs children? They are just a personal choice, society doesn't need a next generation. Are you really unable to see any societal value in having a next generation of Americans, or perhaps I am misunderstanding you, and you were being sarcastic?
Virtually every western nation is facing a social security crisis because there are not enough young people to support the retirees. America is about the best off compared to any developed country because of our immigration. Italy, Japan, Germany, France, they're all facing bankruptcy in their retirement programs. Personally I find that the least of the reasons for wanting to produce a next generation of human beings, but for selfish pragmatic reasons alone, it should be clear that society cannot function when everyone wants to live off someone else's children.
By the time you factor in the costs (2nd car, wardrobe, having strangers raise the kids, etc.) of a 2nd income, the 2nd income is pretty much eaten up.
You make a very valid point on this one. Virtually all second jobs produce a negative return for the family, unless the wife is in the tiny percentage of high-paying jobs like doctor or lawyer. In addition to the costs you've already mentioned, don't forget taxes (the second income is taxed at a much higher rate since you've already used up your deductions) and food (2-income families spend enormous amounts of money on prepared food, affecting not only their budget but contributing to the obesity epidemic in America).