nope... it is not no tone...
males are able to sing it better than females using falsetto for higher notes, thats a known fact...
whether it is easier to go off- key depends on the person itself, but thbe person must be able to control his breath and diaphragm well...
Bee gees are very nasal, pop singing, not a very good example...
coldplay, that is more of a technique....
if you want to, there is a group of all male counter- tenor choir where they sing only in falsetto... very good...
counter- tenor is a part in a choir though not very common where males sing above their normal range....