The term inborn means, existing from the time someone is born. Characteristics and traits naturally passed/inherited from parents to their children through the genes is referred to as hereditary. The approximately 40% children have the same characteristics of the voice as their parents.
I’ve heard that people inherit 50% of their personality traits from their parents, 40% from their environment, and 10% are from other general varying factors.
In my opinion, I think more than half of people posses and display similar voices to that of their parents.
This form of similar traits is also the same with musical instrument families. This is because the sounds will be distinctly similar, if the structure is similar.
Note1:Even if the figure of the larynx is similar, the voice is changed by the background or how a person uses it. For example, with accents, and intonation as well as environmental factors. Although it is sometimes difficult to change the voice consciously by means of environment.
Note2:Even if not a blood relative, the voice becomes similar to those people in your environment. That is because of a mirroring effect, which can be noticeable when people live together for a long time.