How does THIS work? Celtic women give birth to Celtic girls while Nordic men give birth to Nordic boys?
You realize that it takes TWO genders to make a child, right?
APf
some types of DNA/RNA which are used for population studies come down via the mother, and others via the fathers.
And the Vikings probably killed all the men but married or made concubines of the women.
DNA can be tracked back through generations, male & female. Research it and join the 21st century.