yes , if you want that the ears looks bigger on a child than they are, you shall continue with 200mm lens instead of a shorter lens as 135mm , 85mm or 50mm
A head/shoulder shot of a young child using a full frame and 50mm lens needs about a 3 foot subject to camera distance to fill the frame. For me, it's much more probable to photogragh a kid substantially further away. At 12 feet, a particular perspective and subject proportions are observed by the human eye. If I shot it with a 50mm lens, which is considered very close to what a human eye sees, I've captured these perspective and proportions observed at 12 feet distance. If I then crop the shot to end up with a head/shoulder shot, I have not changed anything I observed with the naked eye or what I photographed, and I end up with exactly the same perspective and proportions as if using the same 12 foot subject to camera distance and using a 200mm lens so it fills the frame with a head/shoulder shot. No? Isn't the magnification of a 200mm on a full frame 4X and 3 feet times 4 equals 12 feet?
Sure you can argue you don't like what it looks like with the 12 foot distance/perspective, or that a kids ears are too big in your opinion, or a girl is too fat in your judgement, and even argue that both could benefit asthetically from the skewed and inaccurate proportions that shorter pespectives and focal lengths afford in order to mask a reality, but it doesn't make sense to me to claim that longer focal lengths make for disproportion, when in fact the opposite is true.