Why is it difficult to diagnose genetic conditions?

The main reason it can be hard to reach a diagnosis is simply because a disease or disorder is so rare that it is unrealistic for a doctor to be familiar with every one of the thousands of rare conditions. Another reason that it can be difficult to diagnose a rare disease is because many of these conditions are genetic.

children tend to take more after their grandparents more than their parents. it’s the dna you received that was passed down to you somewhere in your family. maybe one of your grandparents had/has straight hair and you might have gotten it from them.