I'm definitely not a geneticist, but when you have an older child with blond/white hair, blue eyes...how are the odds that the second child (both girls) have dark brown hair and brown eyes ?
In my case...Both of my boys look like their father (I was only the test tube to carry them in ! ha)...
There were studies done in Australia and Cali. Stat's showed something 15-20% of kids weren't the "dad's".