Children who came from frozen embryo, egg, or sperm may well be described as literally "cool" kids.

Freezing or cryopreserving gametes (egg and sperm) is a form of fertility treatment for couples who have difficulty conceiving. Some celebrities have resorted to the expensive technique like TV host Korina Sanchez.

Sanchez reportedly froze her eggs when she was still busy working and could not yet make a family. The egg was later fertilized in the lab (in vitro fertilization) using her husband Mar Roxas's sperm. They eventually had twins, a boy and a girl, via a surrogate mother.

IVF may also involve a frozen embryo. The first such procedure successfully produced Zoe Leyland in 1984. Since then, more than half a million IVF babies have been born from embryos frozen at a controlled rate and then stored in liquid nitrogen, according to Wikipedia.

Frozen embryos can become twins, the first of whom were born in February 1985. Twins Lydia and Timothy Ridgeway, who were born on 31 October, are extra special though.

Parents Rachel and Philip Ridgeway already have four other children, ages 8, 6, 3, and almost 2, none conceived via IVF or donors, according to CNN. Their newborns, however, won't be biologically related to their older siblings as much as themselves because they came from one of few embryos created for an anonymous married couple — a husband in his early 50s with the egg coming from a 34-year-old donor, CNN reported.

More shocking is that the twins, though the youngest of the Ridgeway siblings, are paradoxically the oldest of them since they came from embryos frozen on 22 April 1992 or 30 years ago.

The couple who created the embryos donated them to the National Embryo Donation Center in Knoxville, Tennessee, United States so another couple might be able to use them, CNN said. The embryos were thawed on 28 February and implanted on Rachel 2 March.

Before the Ridgeway twins, there were Emma Gibson, who was born from an embryo that had been frozen for 24 years, and her sister Molly who was born in 2020 from an embryo that had been frozen for nearly 27 years.

Interestingly, sperm preserved for an even longer time can still be used to fertilize an egg today and become a healthy newborn nine moths later. IVF experts say sperm hundreds of years old can actually be used to make a baby if there is a law allowing it, according to The Guardian.