Why using -son instead of -daughter? [closed]

Solution 1:

In English, family names are usually passed down from a father to his children without any changes. So if a man is named Paul Johnson, then all of his children, regardless of gender, will also have the last name Johnson (not Paulson or Paulsdaughter). If one of those children is named David Johnson, then all of David's children will probably have the last name Johnson (not Davidson or Davidsdaughter).

At some time in history, centuries ago, the name "Paul Johnson" really would have meant "Paul, John's son." However, names no longer work that way in English-speaking countries.