Hargreave M, Jensen A, Hansen MK, et al. - Researchers conducted this retrospective cohort study to explore the connection between different types of fertility treatments and cancer risk in children. Between January 1, 1996, and December 31, 2012, 1,085,172 children born in Denmark were included. According to findings, the risk of childhood cancer for those born after the use of frozen embryo transfer vs children born to fertile women was significantly increased (44.4 vs 17.5 per 100 000 person-years, respectively; hazard ratio, 2.43). The risk associated with using other assisted reproductive technology, including in vitro fertilization, intracytoplasmic sperm injection, or hormonal treatment, was not significantly increased. Overall, the authors concluded that a slight yet statistically significant increased risk of childhood cancer was related to the use of frozen embryo transfer.