This is a good question that doesn’t have a good answer. Some experts suggest if a person always sits or stands in a slouched posture, then over time the body assumes that position permanently.
There are some social theories about tall people or large busted women assuming a stooped position to hide their height or body parts.
A forward head and forward shoulder posture is seen in people of all sizes, shapes, ages, and gender. If there is a genetic trait for poor posture, no one has found it yet.
It’s clear that problems occur with a forward head or slouched posture. Pressure on the spinal nerves can cause numbness and tingling down the arm. Muscles get out of balance when the upper body is held in unnatural positions for long periods of time. Shoulder, neck, and upper back pain can occur.
Researchers are looking into the use of taping to help correct the posture. The goal is to improve muscle function and reduce pain when present. Short-term results have been reported but long-term studies are needed.