My sister and I are trying to find out if our dad shares the same father as his brother? My dad and uncle share the same mother but we are not sure if they share the same dad. Being as though my dad is decease we can not run a DNA test with his brother. My uncle is still living and from what I have read we cant run a yDNA test because we are females; however my uncle is a twin and his twin is a female. Is there another way we can tell if my dad and his brother share the same father?