Irish, Mirage is correct in stating that it's not genetic. It's the way that children are raised and how they are treated by their parents and other authority figures. They were stunted emotionally at a very early age, i.e., weren't allow to state how they felt, had to hide their true feelings, no affirmation, love, and validation from their parents. The children may have been compared to another sibling that may have been a "shining star" in the family, thus, always been compared to someone who excelled in other areas, but the child who had to play second fiddle could never meet the high expectations set by another sibling, parent or authority figure.
I also agree that you have provided tools to your daughters. They are seeing how you are a calm man w/lots of patience. Your home is a stable one and that goes a long way w/children. They know that you love them and will be there for them. Their chances of having a MLC are less than those of children who are dealt the blow of not being recognized for their accomplishments, etc.
I think you are doing a wonderful job in raising your daughters.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.