Response to The Letter to the Editor by Alfred Körblein concerning “ Atomic bomb testing and its effects on global male to female ratios at birth

In the recently published paper, no direct claims were made since only relatively indirect global ambient radioactivity levels are available [1]. However, available data from reputable sources clearly shows a global annual average population radiation exposure that peaked in 1962 and 1963 shortly after a spike in atomic bomb testing that pre-empted the Partial Test Ban Treaty of 1963 [2]. Ambient global radiation levels fell progressively thereafter. Korblein’s statement that WHO data only goes as far back as 1970 is incorrect. For most countries, data is available as far back as 1950, and this data has been used not only to review country level data, but also data at continental level [3, 4, 5]. Korblein also performs analysis for the US and five large European countries. The dataset used in the paper in question had far greater power due to the larger numbers involved (all countries reporting births to WHO, worldwide) [2]. Moreover, Korblein attempts to link his analysis to annual cesium-137 concentrations in grass samples at Rothamsted, north of London in the UK [6]. This is arguably a rather narrow perspective from which to attempt to assess global radiation trends. A possible explanation for the delay in radiation effect on the gender ratio at birth is the obvious fact that windborne radioisotopes generated by atomic bomb tests would have to travel around the world and eventually fall to the ground by precipitation. Indeed, the study demonstrated that overall, 94.5% of the