By "uni-sex schools," do you mean a school with students of both sexes? "Uni-sex" schools is not the usual term. In the United States, the usual term is "coeducational schools" (or "coed" for short).*

I have heard women claim that women learn better in an environment where they don't have to deal with the tendency of men to domineer. That might be true.

In general, I think coeducation is healthier in every respect. Making a mystery of things only heightens the lure of the forbidden. In the 1960s, I attended Harvard Summer School. In those days, women were normally barred from the Lamont Library--the main undergraduate library; but in the summer they were admitted. I was astonished to hear a year-round Harvard student complaining bitterly. He said that he could not concentrate on his studies with women in the library. I thought that was bizarre. Having attended coeducational schools all my life, I accepted female classmates as a normal part of school.

*OxfordDictionaries.com includes "co-education" (with a hyphen) under "British and World English" so I think it is the usual term in British English as well.

I am against segregation in the school environment.

School is not only about learning theoretical subjects.  It is also about learning to interact with other human beings, and learning to work and function together.  If you segregate the sexes, you increase the inability of the two to be able to normally and healthily interact later in life.  I believe that it will just lead to more marital problems for those kids later in life.  How can one wisely choose a life partner, when they don't know how the other sex behaves? Or how can they understand how to get along, if they have been isolated from people of the other sex for years?  There are differences between boys and girls in behaviour (usually), and school is an excellent opportunity to learn about these differences.   No theoretical course can teach you that.  You must interact.

The feeling that the boys are strange creatures that we girls must consider outsiders (or the opposite) is removed.

Also, it diminishes the chances that the one group (boys or girls) will feel inherently superior or inferior to the other group, as in school girls and boys tend to perform at a very comparable level, and seeing this eliminates the misled belief that one group is smarter or less smart than the other.  This reduces discrimination later in life. 

I also feel that having both males and females in one's routine environment brings a sense of comfort and diminishes wild behaviours.  

(Note, regarding what was written above, about dorms, that is a totally different issue, I don't know what it has to do with this.  Because you go to the same school, it does not mean you have to sleep in the same house or the same dorm! I fully disagree with dorms shared by boys and girls.)