A review of terrorism and its reduction of the gender ratio at birth after seasonal adjustment

Abstract

Background: Males are born in excess of females, a ratio expressed as M/T (males:total births). The ratio exhibits seasonal variation. Furthermore, acute stressful events may result in a transient dip in male births due to excess foetal losses, reducing M/T.

Aims: This study was carried out in order to identify significant M/T dips after adjusting for seasonality.

Study design: Live births by gender and month were sought for acute stressful events. After seasonal correction (where appropriate), M/T dips were sought.

Subjects: Live births.

Outcome measures: M/T dips.

Results and conclusions: This paper studied 112,226,306 live births. The following events showed dips ≤ 5th percentile 3–5 months after these acute episodes: the Brooklyn Bridge protests, Katrina Hurricane for all 4 states and for each individual state (Alabama, Florida, Louisiana, Mississippi), the Battle in Seattle, the London bombings, The Madrid bombings (for Madrid and for Spain), the Breivik shooting, the Oklahoma City bombing and the Sandy Hook Elementary School shooting. The Virginia Polytechnic Institute and State University shooting the Fukushima Daiichi nuclear disaster also showed dips albeit slightly later.

Seasonal adjustments should be taken into consideration in order to avoid Type 1 or 2 error pitfalls.