In one study, scientists analyzed population data from 1964 to 2007 in the United States and 39 European countries  They found that between 1964 and 1975, the birth rate of boys was higher than that of girls in all countries  A similar phenomenon occurred in many Eastern European countries after 1986  Scientists have analyzed that this phenomenon is closely related to nuclear power plant leakage and nuclear testing caused by radiation leakage
Research data show that after the Chernobyl nuclear accident, the proportion of new boys born in Belarus, near Ukraine, was higher than in france, which was further away
 The former appears mainly related to atomic experiments in the 1960s and 1970s, while the latter is likely to be linked to the Chernobyl nuclear accident