While driving around this early morning with my son, I heard a segment on NPR that made me scratch my head. It was about couples in their twenties who decide to raise a child together, but who do not get married because they feel marriage is too big a commitment at this stage in their lives: Andrew Felices, 26, and Mellissa Giles, 27, are this new face of the American family. They've been living together since before their son, A.J., was born. He's 2 1/2 now, and he shrieks gleefully as he sprawls on the basement floor with dad, building a train track. The couple bought a cozy condo in Frederick, Md., last summer. A home, a child — but neither is in any rush to tie the knot. "We're still young," Mellissa says. We're enjoying the time as it is." I was rather puzzled by this. The implication is that having and raising a child together is less of a commitment than getting married. This is shocking to me. In my moral universe, the s