How are you going to do equal number of boys and girls? Are you going to restrict registration when the number of boys and girls are not equal and wait till it catches up? How are you going to monitor the ratio when you have open registration? Are you going to refund some people's money saying sorry we have to maintain the ratio?

What is an acceptable ratio for you? 1 to 1 or upto 5 boys to 1 girl. What are the metrics that you are going to stick to?