For Alan and Louise Masterton, the death of their daughter, Nicole, had a uniquely cruel twist. It was terrible enough that the3-year-old succumbed to burns suffered in an accident at the family's Monifieth, Scotland, home in 1999. But for the Mastertons, Nicole was more than just a cherished child -- she was a chromosomal miracle. The couple had spent 15 years trying to conceive a girl, bearing four sons in the process. When Nicole finally arrived in 1995, the Mastertons… more