Q: Can average-size people become the parents of children with dwarfism?
A: Yes, more than 80% of children with dwarfism are born to average-height parents. Most are caused by a spontaneous genetic mutation or changes in the egg or sperm cells prior to conception. Other conditions are caused by genes inherited from one or both parents. In either of these cases, two average-size parents can have a child with a form of dwarfism (though this is far more likely to occur with a spontaneous mutation).
What prompts a gene to change is not yet clearly understood. The change is seemingly random and unpreventable, and can occur in any pregnancy. Generally, when average-size parents have a child with a form of dwarfism due to a spontaneous mutation, it is rare to have a second child who is also of extreme short stature.