Scientists recently conducted a retrospective study to analyze the sex ratio of babies born in the United Kingdom via assisted reproductive techniques. METHODS: 106,066 offspring born by assisted reproductive techniques in the UK from 2000-2010 were selected, and the study involved 76,994 women treated with assisted reproductive techniques (including artificial insemination, first-generation IVF, and second-generation IVF). The results found that the boy/total offspring ratio was 0.521 for women treated with first-generation IVF and 0.493 for women treated with second-generation IVF. the male/female ratio of offspring born to women who underwent blastocyst transfer was 6 percentage points higher than that of the group that underwent oogenic embryo transfer. This result was published in the American Journal of Reproduction and Infertility in 2014.