Increases in childhood cancer near nuclear facilities in France and in Germany as well as elevated human birth sex ratios after the atmospheric atomic bomb tests and after Chernobyl motivated the inspection of the secondary sex ratio and the corresponding gender-specific birth counts in the vicinity of nuclear facilities. Focus is on which changes in the birth counts go along with significant changes in the sex ratios. Official municipality-specific annual birth counts by sex for all of France and for whole Germany are updated until 2016 and 2017, respectively. Using logistic regression, we determine significant change-points (jumps) after distinct radiological events in sex ratio time-trends in circular areas around pertinent nuclear facilities. With Poisson regression, we quantify the corresponding change-points in the trends of absolute annual birth counts for boys and girls. In the 35-km vicinity of the 'Centre de l'Aube Nuclear Disposal Facility (CSA)' in France in the year 2000, we observe a jump in the sex odds (SO) with sex odds ratio (SOR) 1.101; 95% CI: (1.033, 1.175), p-value 0.0033. This jump in the sex odds can be associated with a drop in boys of 3.44% ( - 4.02, 10.37), p-value 0.3561, and a drop in girls of 8.44% (1.33, 15.04), p-value 0.0208. In the highly populated area around the nuclear power plant Philippsburg in Germany from 2001 onward, we see a similar effect: SOR 1.027 (1.008, 1.046), p-value 0.0045; drop in boys 5.56% (2.24, 8.76), p-value 0.0012; drop in girls 6.92% (3.62, 10.10), p-value < 0.0001. The presented findings corroborate and specify earlier observations and call for intensifying bio-physical research in exposure mechanisms and exposure pathways of natural or artificial ionizing radiation including neutron radiation and neutron activation. Reinforced biological and epidemiological research should aim at clarifying the associated genetic and carcinogenic consequences at the population level.