The frazzled-sounding greeting on new mom Alex Patrick's cell phone tells the story: “I'm up to my neck in nappies and bottles. I'll get back to you as soon as possible.” Well, maybe not the whole story. That's because the bundle of joy now monopolizing Patrick's time—7-month-old Charlie—isn't exactly your typical progeny. In fact, the baby's very arrival into the world was a unique family affair.

Six years ago, Alex, 32, an environmental consultant living in south London with her husband, Shaun, 39, a mechanical engineer, was eager for a baby. But around Christmastime of 1999 she was diagnosed with cervical cancer, and treatment for it eventually left her infertile. That's when her sisters stepped up to the plate. Identical twin Charlotte Pestell offered to donate an egg, which doctors fertilized via IVF with Shaun's sperm. Since Charlotte had suffered difficult pregnancies of her own, the healthy embryo that resulted then passed to another of Alex's sisters, Helen Richie, 35, who easily carried it to term in utero. The result? The birth on June 19 of 8-lb. 7-oz. Charles George.

If that's all a little complicated to log into the family scrapbook, says Alex, the bottom line is simple: Charlie's the result “of all the love that went into creating him.” Or as Charlotte puts it: “He's got all our best bits.”