In Asia Boys Are Number 1

Throughout Asia there the gender gap continues to widen as the preference for male children continues unabated. India's 2011 Census reflects this as there are 914 girls for every 1,000 boys that number has dropped 13 percentage points since the last Census was taken.

China's One Child Policy has so skewed the ratio of men to women that

A study by the government-backed Chinese Academy of Social Sciences named the gender imbalance among newborns as the most serious demographic problem for the country’s population of 1.3 billion.
“Sex-specific abortions remained extremely commonplace, especially in rural areas,” where the cultural preference for boys over girls is strongest, the study said, noting the reasons for the gender imbalance were “complex”.

Its estimated that by 2020 24 million Chinese men will be unable to marry.

India has seen the problem become more acute with the introduction of ultrasound machines insuring that a male child is born.

The reasons for the gender imbalance in India and elsewhere in south Asia are complex and historic. Many patriarchal communities traditionally prefer sons because they will inherit a family's wealth without it being "married" into another family, because it is believed they will better care for elderly parents and because a family will earn a dowry upon a son's marriage, rather than having to pay one out for a daughter's. This has led to widespread sex-selective abortion – officially banned two decades ago – which has increased as ultrasound machines have become cheaper and more ubiquitous. Nowadays a test can be had for less than £150.