It is said that if your parent haven't talent, you may be same as parent. It is known also that the quality of human is inherited from the many ancestors, so if you have a talented ancestor, you may be a talented person. But you have no ancestor having a genius, you may be disappointed as you have no ability.
There is the rare disease as one in 17,400 named familial adenomatous polyposis(FAP) which is inherited 50% from parent. But there are 30% cases whose parent has no abnormality of APC genetic code in all FAP cases. They are known as a new born mutation. We are able to know that if you haven't some gene, you may have a mutation of slight percent from this data. Therefore if you have no hereditary good gift, you might be a phenomenon by a mutation. If you haven't talented parent, you should have confidence as you might be a genius.