At the moment I am just using the UN data for total population (no sex ratios). I simply divide the numbers by 2 to get the two sexes. I need to upgrade this using the UN data which includes each sex separately.

No excuse for this it was just laziness, I started development using the total population data and did not get around to changing it. It is first on my list of upgrades.

The use of equal sex ration will make little difference to long term world projections. However it could be significant for some countries.