The international service of Czech Radio 
29-11-2020, 11:23 UTC

1986: fewer baby boys than baby girls - because of Chernobyl?
In November 1986, for the first time in half a century, doctors reported that fewer boys had been born than girls. Many scientists are convinced that this was caused by the radiation from Chernobyl. Embryologist Miroslav Peterka claims that because of the accident in Chernobyl, 450 boys were aborted. He came to the conclusion by comparing the birth-rate statistics of boys and girls over a longer period of time. Normally, the proportion is around 105 boys to 100 girls. In November 1986 it was vice-versa.
According to Miroslav Peterka, the cause of this drop in the birth-rate of boys is the radioactivity that affected women in their 8th -12th week of pregnancy. The brains of the foetus are more sensitive to radioactivity during this stage of development and the male foetus is more predisposed to abortion. According to Peterka’s calculations, North Moravia had 199 boys less (-17%) than is the statistical average, in the south 161 boys less (-15 %), in eastern Bohemia 47 boys less (-7%) and in Prague 35 boys less (-6%). In northern and southern Bohemia, which due to better weather conditions were spared radioactive rain, the ratio of boys to girls born that month was normal.