Perhaps the reason that there is a disparity in the number of marriageable young men and women in the frum community lies in the different rates the two groups diverge over time.
Suppose about an equal number of boys and girls are born in a community in the year 1989.
By 2009 the numbers may no longer be equal for these 20 year olds.
It appears that there are more girls than boys in a given age group.
Perhaps fewer boys than girls survive to a given age due to accidents or illness.
Perhaps a greater number of boys than girls have mental health problems that make them unsuitable for Shidduchs at that time.
Perhaps a greater number of boys than girls “drop out’ of the yeshiva world and are thus no longer in the pool of shidduch candidates.
Perhaps if we know why there is an inequality we can take steps to remedy the problem.