Texas triplets born years apart

McKINNEY, Texas (CNN/WFAA) - The last of three triplets was recently born in North Texas. That's not too unusual, until you consider that the youngest and oldest of the triplets are four years apart in age.

Having a hard time wrapping your head around that? Let us explain how medical technology made it possible.

Andrew Gracin is the third of Chris and Joyce Mallon's children. Andrew, 4-year-old Julianna and 2-year-old AnnaSophia were all conceived in a petri dish on October 26, 2007.

Julianna was born nine months later through in vitro fertilization. Her brother and sister waited their turns in frozen limbo. And then they each got their chance to be born.

"Sometimes when you pray for a miracle, you get three. And so that's what we have," said Joyce Mallon.

Joyce calls them "triplings," since they are triplets by conception but siblings by their dates of birth.

Fertility experts say freezing techniques have improved, so embryos can now be preserved for longer periods of time. An estimated 400,000 embryos are currently in frozen storage in the United States.