There are two places on Earth where I think men and women should be separated; sports teams and bathrooms. Other than that, men and women should use all the same facilities, especially universities.
In life, there is no great divide between men and women, so why should there be in schools?
The North American colleges have been moving towards a system where both sexes are permitted to enter all programs. This is basic civil rights. But opening overseas campuses, such as in Saudi Arabia, that do not accept women sends the message that civil rights are not important in certain countries. These colleges should be pushing for civil rights in all countries, and allowing women to attend in Saudi Arabia will reinforce this ideal.
I think that any educational institution can benefit from gender diversity. This is 2016 and gender should no longer matter when it comes to education. Having said that, I do think that all colleges should admit both sexes. Personally, I would not be interested in going to a college with only girls attending.
I completely believe in gender equality but I don't believe that's what's being discussed. I think if a college wants to admit only one sex, that's fine (although I don't know how they treat different gender identities). It's not as if there aren't schools that aren't just composed of a female body.
I think, in the creation of these types of schools, it's more the thought process that young men and women are being separated for another 4 years and so they're safe (which is admittedly stupid). I don't think it's because the school believes the opposite sex is too stupid to be admitted or too corrupting (or corruptible), which would be an issue. So if the former is the ideology of the school than whatever. If it's the latter, than you're segregating a large portion of society for idiotic reasons, so stop.
There are many high schools in the USA that only allow one gender. Colleges do not have to be coed because at 18 these students are technically adults and if they want to meet people from the other gender they will find a way. Some schools, like Wellesley, pride on the fact of developing young minds in a single gender school and if they want to keep it that way, that is okay.
Colleges should be allowed to select the sex of the students that it wants to attend its universities, unless it is a publicly funded university. Private institutions should not be required to follow such laws. We may not like the standard, but as a private institution, it should have the choice. There are plenty of other universities that treat all people equally.