A D.C. couple wants children, but not now, and are worried about infertility creeping up on them as they get deeper into their thirties. They came up with a novel solution -- donating frozen embryos to their future selves. The procedure is not uncommon for couples with fertility problems; will it become a popular insurance option for young couples who just aren't ready for kids? They might want to think about what to do if they have more embryos than they want. Or what happens if they get divorced.