Christians believe that marriage is an institution ordained by God, and every marriage is thus blessed. However, in ordaining marriage, God commanded man to "be fruitful and multiply." This commandment has never been repealed or amended, no matter what any Malthusian population-control fanatic tries to tell you. One trend that has undermined marriage has been the rise of the Contraceptive Culture, which celebrates sterility as the norm and views fertility as a pathology requiring medical prevention.You should read the whole thing.
How many Christians have embraced this false -- dare I say, evil -- worldview? How many young Christian married couples use contraception because "we can't afford children now"? And how many married Christian couples have unwittingly subscribed to the Zero Population Growth ideal of exactly two children per couple? Did you know that surgical sterilization (tubal ligation) is the No. 1 form of birth control for American women? It's the "two and tie 'em" mentality: Have exactly two children, then get yourself surgically sterilized. . . .
UPDATE: In the comments at the Green Room, Anna writes:
My husband and I were married at 21. . . .Anna, once you understand that their criticisms of you are actually a defense of their own decisions, this anti-baby attitude becomes more comprehensible. People can always justify their own behavior, and people who embrace the Contraceptive Culture typically display these attitudes. Negative conceptions of others -- the "trailer trash" stereotype of large families -- are a defense mechanism to enhance their own self-concept.
What galls me is the anti-child atmosphere nowadays. We have 3 kids (including a set of twins), and we'd love to have another. We aren't really in a position to have another right this minute, but the door is not shut. However, mention this to my (devout Lutheran) in-laws, and they rant about how they'll kill my husband if I get pregnant, and how they don't 'need' any more grandchildren. We even hear from other members of their church about how we're too young to have so many kids - how are we going to pay for college/cars/etc for not only them, but for ourselves. We’re 26/27! How is that too young? There are only so many times that I can retort with "We're old enough/it's our family/you can take out loans for college, but not for retirement!" before I have to run to the bathroom to cry.
Believing that their way is the only way, they must necessarily believe that, by marrying young and having lots of babies, you are dooming yourself (and your children) to misery and poverty. The "how will you pay for college" question is meant to be the ultimate "gotcha." My daughter's working her way through college. Next question?
UPDATE II: More wisdom in the comments (here) from father-of-five Larry:
I cannot count the number of times we have been unintentionally insulted by well meaning, self-identified Christians, asking if we know what causes that (pregnancy) . . .To which I always answer, "Yes, and we're very good at it." That shuts 'em up quick.