With respect to Bishiwnen and Dana_H, that would only work if we use the computer model of genetic reproduction.
I realise it may seem so obvious especially since, (or because), it has seemingly become so ubiquitus. But the reality is, it is just a perspective.
The previous model, of a chemical response, was equally perspective. We tend to dismiss ideas that predated the discovery of DNA, somewhat arrogantly, especially as we begin to have some comprehension of the actual complexity of genetics.
We need to have some proper understanding of the difference between male and female first. The presumption that it's all about a single chromazone, either having an extra bit or not, isn't necessarily exact. Equally, the presumption that males make sperm while females make babies is very generalised. Rather like assuming Americans like baseball while Britons like football.
To emphasis this, how many of us have actually had our own chromazones sex tested? How many humans?
If it is all a simple matter of a single chromazone, that would suggest that the outcome would be definate. Yet it clearly isn't. There are enormous variations in behaviour, aspiration and sexual attraction.
I apologise for appearing pedantic, but like I suspect others, I learnt, after finishing A leval biology and assuming I knew everything, that nothing in life is ever that simple, especially human life. And the accademics who are feeding us with information have an annoying habit of only tellingn us what they think we need to know.
Sex determination is infinately more variable than a male female duality.