a) how important am I and is behavior/trait X to my parents? VS b) extra-familial socio-cultural conditioning aka "how important, from the POV of marketing/superEgo, is behavior/trait X is to my parents AND/OR all the candymen?" c) deception by previous and within same generation. Are you strong enough to be yourself VS are you strong enough to adapt to an in group that wants you to be a part, a slave, some example?

The physical changes are most likely not directional but are tuned by how much a parent cares and how strong he, she, they are to make sure this desire/caring is obvious.