Lets do some math.

Lets assume that 18 to 50 is the child bearing age for women. The 2011 census data says that the total number of women between the ages of 18 to 50 were 288 Million. There were some more who did not state their age but its a pretty small number (0.4%) so I'm ignoring it.

The % of Hindu's is around 80% so I'm gonna assume that % for all age groups as an approximation which gives us 231 Million Hindu women between 18 to 50 as of 2011.

If we came up with a rule that said every hindu woman between 18 to 50 must bear at least one child per year for the next five years (starting 2011) then we'd have 1.15 Billion Hindu kids in 2011. Thats already almost equal to the population of the country.

In 2012, the girls who were 17 in 2011 would now fall under the rule and the women who were 50 in 2011 would no longer. So again we use the census data to work out that there would be 230 Million women in 2012 giving us another 1.15 Billion Kids.

If we continue the progression until 2015 we would have generated a total of 5.9 Billion new Hindu children in the last 5 years. By 2015 our total population would have been 7.4Bn. Thats about equal to the entire population of the world today.

These new kids would all be between 1 to 5 years old so they wouldn't have add any productive economic output. So our GDP should remain the same at 2.047 Trillion USD but because our Per Capita GDP which is ~1600 USD now would instead be ~285 USD.

That would make us one of the poorest countries in the world comfortably below countries like North Korea (583USD) and Congo (397USD). The only competition could be places like Malawi which according to IMF is at 222 USD and Burindi which is at 303 USD.

5 kids doesnt sound like such a great idea after all.