Mod 80:
True, one can not determine the amount in the frum community, but is the frum community any different from the rest of the world? How are our birth rate different or special from no frum or non Jews?
In addition, the world census provides the FACT of how there are more boys than girls in the world. Using that assumption, one can additional assume there are also more boys and girls in the frum world since frum people do not grow horns on their head and most of us fall into a normal range. As far as the explanation in Biology, the Gemorah in Niddah 31A, deals with this a little and there are numerous studies that indicate how halacha favors boys. Again, hamyvin yovin.