It's a Girl! looks at the devastating real-world effects of the one-child policy in China and two-child policy in India.
The film which was directed by Evan Grae Davis takes us to China and India where the number of children you can have is restricted by law. If you have more than this quota then you have to pay the government a fixed "fine" or worse. The principle behind this law is a logical one in that the outcome is to slow down population growth and from this perspective, it is working as an estimated 400million births have been avoided as a direct result.
The tragedy comes when parents do not know the gender of their child before birth, or find out that it is a girl during pregnancy. In China and Inda having a baby boy is considered to be much more desirable as he will be able to continue the family name among other cultural things. If the one-child policy was not there then the parents would likely just try and have more children but instead we are seeing "gendercide". Even if the girl was to survive she would likely have a life of hardship at the hands of parents simply just for being a girl, in western culture this sort of mindset would be outrageous but in these countries, it is simply part and parcel with culture.
Ultimately what Evan Grae Davis is aiming to achieve with It's a Girl! is to raise awareness around the world about what is happening, so that something can be done about it and girls can live free happy lives.