Please consider the wider implications of having more than 2 children.
We are already living way beyond the means of this very finite planet. If there are 1 million more humans every 5 days how on earth will we ever feed them, and slow climate change?
Having big families is simply self-indulgent.
Watch David Attenborough's Horizon from 9/12/2009 via Youtube or visit the website of The Optimum Population Trust for a very detailed discussion of the facts.