Also, there were the sons of Reuben, the firstborn of Israel. For indeed, he was his firstborn, but when he had violated the bed of his father, his right as firstborn was given to the sons of Joseph, the son of Israel, and he was not reputed as firstborn
Other versions
King James Version
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.English Standard Version
The sons of Reuben the firstborn of Israel (for he was the firstborn, but because he defiled his father's couch, his birthright was given to the sons of Joseph the son of Israel, so that he could not be enrolled as the oldest son;New International Version
The sons of Reuben the firstborn of Israel (he was the firstborn, but when he defiled his father's marriage bed, his rights as firstborn were given to the sons of Joseph son of Israel; so he could not be listed in the genealogical record in accordance with his birthright,