Well, I'll give you some practical reasons for that for starters. I'll hopefully be able to give you more satisfactory ones tomorrow, but no promises. This is in the order I think of them, not of importance or relevance:

1. Priests very often live with other priests. It would be very complicated to have to have separate dwelling-places for priests for a single parish. There is a reason that people who struggle keeping their sexual tendencies under control aren't usually allowed to become priests.

2. Because men tend to have a harder time connecting with their Faith, it helps to have an important and special role for them that doesn't make them feel that religion is for women. This sounds silly when summed up like this, but it comes down to the way men and women differ.

3. You may note that men are almost always the leaders in history. This isn't in and of itself a reason, but an indicator that men may be better suited for public leadership, with women being better suited to direct things "behind the scenes" and taking care of people on a more personal level, rather than caring for large groups in a less personal way. Note that this is a different type of leadership than a government position, which is a job, unlike the priesthood which is properly a complete dedication and surrender to the will of the God and the Church. Monarchy is comparable in some ways, but one isn't chosen for monarchy based on leadership qualities but on birth, so it isn't a double standard to support woman monarchy but oppose woman priesthood.

I'll try to add more later, as I said, but later might end up being several days for now--it takes a while to answer these questions, which are asked with such ease.

To help me answer your question properly, could you give me your reasons for thinking women should be allowed to become priests?