[user5454]

But worse for your knees...

[badosu]

Squatting is a more natural position for evacuating

[chimeracoder]

A proper squat puts zero pressure on the knees. That's why people with ACL injuries are still able to do squats.

Grab a copy of a basic barbell weightlifting book, and you'll see - it'll say the same thing.

[aeorgnoieang]

Maybe what the other commenter was referring to was something like weak leg muscles that manifest as pain in or around the knee.

[zhte415]

A lot depends on the age from which you've been squatting. I don't mean weight-lift squats, just squatting on the ground.

Most people from Asia are able to squat pretty comfortably, comfortably as in heel on the ground and not exerting any calf or knee tension, having done it since childhood. Most Western Europeans and Americans can no, the heel of the foot doesn't rest on the ground and squatting is done on the ball of the foot therefore calf and knee pressure.