Generally, around the globe there are 105 boys born for every 100 girls. however, recently in some countries, this ratio has been altered with a much larger proportion of boys being born in some countries. the primary reason for this shift to a higher proportion of male births has been

The practice of female infanticide.

Explanation:

Some countries, especially China, India, have practiced female infanticide due to the fact that they regard males as superior. As for China an addition factor might have been the one child rule applied for a long time although this law has been relaxed in the last few years and you can now have 2 children. Also, India is well know for female infanticide and women are less valued and the fetus is aborted.

https://www.economist.com/international/2017/01/21/the-war-on-baby-girls-winds-down

India has cause to fret. According to two demographers, John Bongaarts and Christophe Guilmoto, a staggering 45m girls and women are missing from the country. Some were never born, having been detected by ultrasound scans and aborted. Others died young as a result of being neglected more than boys. Some villages in the north have an alarming surplus of boys and young men. Yet attitudes and behaviour are changing. In India, and in the world as a whole, the war on baby girls seems to be winding down.