If a 16 year old boy and a 22 year boy have mono, would it be likely they got it from kissing a girl?

If a 16 year old boy and a 22 year boy have mono, would it be likely they got it from kissing a girl?
I got mono before I had ever kissed anyone! While it can certainly be spread through kissing, it can easily be spread through other means, from any contact with saliva or other bodily fluids...accidentally drinking from someone else's soda, for example. I somehow got it from a roommate who was never around. (Probably because we shared cooking utensils?)
It could be from kissing a girl but also from numerous other factors.
Any way they came into contact with mono infected saliva could be the cause:
-Kissing
-Spitting in each other's mouths (Ew, I know this is outlandish)
-Drinking from the same water fountain, bottle, cup, etc.
-Eating after each other
-Sneezing in faces or somewhere else that eventually comes into contact with the face
-Putting your head down on the desk where a Mono infected person drooled/sneezed/coughed/someho... put spit
....
It is possible... But I'm not going to lie. There are alternatives to getting this disease. I have it as well. I aquired it from a 5th grade waterfountain that the janitors refused to clean. I had been the second to get it and the other person probably got it from eating at a resteraunt where they neglected to clean the drinking glasses properly...It's not a very fun thing to have as a 5th grader(they almost failed me).
Possibly. But then again, I had mono when I was 7, and hadn't kissed anybody. It is easily transmitted.