NET

1 The sons of Reuben, Israel’s firstborn—(Now he was the firstborn, but when he defiled his father’s bed, his rights as firstborn were given to the sons of Joseph, Israel’s son. So Reuben is not listed as firstborn in the genealogical records.

Darby

1 And the sons of Reuben the firstborn of Israel (for he was the firstborn; but, inasmuch as he defiled his father's bed, his birthright was given to the sons of Joseph the son of Israel; but the genealogy is not registered according to the birthright,

KJV

1 Now the sons of Reuben the firstborn of Israel, (for he [was] the firstborn; but, forasmuch as he defiled his father's bed, his birthright was given unto the sons of Joseph the son of Israel: and the genealogy is not to be reckoned after the birthright.