Population Model - Can you find the problem here?

Hi - thought maybe someone here would be interested to look at this model and help me determine if there is a problem with the way this model computes, and if there is, how to fix it.

I created this model to compute/analyze the population of a species under some limitations & assumptions which are built into the model. The idea is to look at how the limitations impact the balance of the genders. The issue in question with respect to the performance of the model comes up whenever I set the input of "survival" to anything less than 100% (i.e. when mortality is introduced). To clarify, my hypothesis is that the gender should always remain in equilibrium, however, this doesn't hold true when survival is not equal to 100%.

There is one more wrinkle built into the model which you will see a clarification note about within the model in the assumptions & limitations box.

But remember, the key issue is why when survival rate is not 100% the gender balance is lost. Is the model wrong? If it is, how can it be fixed?