This is a loaded question. You might want to ask about those who used to house corns together but do not anymore because of problems. But asking those who do it is a good way to filter out any negative responses.
It's like asking if being a stoner makes you a loser. Of course those who smoke pot on a regular basis aren't going to tell you what losers it makes them, even if they could see that. Nor will they tell you how it completely stops all intellectual and emotional growth, because they aren't capable of understanding that other people continued growing long after they stopped. They don't get that they are still 13-18 year old mentalities stuck in 30, 40, or 50 year old bodies, they thnk that's what everyone else is, too. So you're not going to get an honest answer of "look at what a pathetic loser and waste of human potential I am."
Anyway, I used to house corns together, when I first got into corns. I found that it caused problems I wasn't even aware of, until I separated them after 2 years. (Then one of them, who was much smaller and a picky feeder with a bad attitude, suddenly sprouted and is an entirely different snake.)
There is no guaranteed method of sexing snakes, and even the best in the world make mistakes, so just because you THINK you are housing two females together, unless they have already both laid eggs, you do not KNOW that they are females and you still risk premature breeding, eggbinding, etc.
There are also issues of stress, cannibalism, and many other issues. There are plenty of good reasons to not keep them together, and there is not one single good reason to keep them together. (IMO keeping more snakes than you can afford is NOT a good reason.)
Just some food for thought. :wavey: