(KUTV) The last of three triplets was recently born in North Texas – four years after the oldest.

Medical technology made it possible for three triplets to be born years apart.

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 26th, 2007.

Julianna was born 9 months later through In Vitro fertilization. Her brothers and sisters waited their turns, frozen.

The mother calls them “triplings” since they are triplets by conception – but sibling 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.

(Copyright 2012 Sinclair Broadcasting Group.)