Sen's original research found that while there are typically more women than men in European and North American countries (at around 0.98 men to 1 woman for most countries), the sex ratio of developing countries in Asia, as well as the Middle East, is much higher (in number of males for each female).
Penelitian asli Sen menemukan bahwa walaupun ada lebih banyak wanita daripada laki-laki di negara-negara Eropa dan Amerika Utara (sekitar 0,98 pria sampai 1 wanita di sebagian besar negara), rasio jenis kelamin negara-negara berkembang di Asia, dan juga Timur Tengah, jauh lebih tinggi (dalam jumlah laki-laki untuk masing-masing perempuan).