Exclusive: A record-breaking baby has been born from an embryo that’s over 30 years old
Cumbersome and explosive In the early days of IVF, embryos earmarked for storage were slow-frozen. This technique involves gradually lowering the temperature of the embryos. But because slow freezing can cause harmful ice crystals to form, clinics switched in the 2000s to a technique called vitrification, in which the embryos are placed in thin plastic tubes called straws and lowered into tanks of liquid nitrogen. This rapidly freezes the embryos and converts them into a glass-like state. The