New American Standard Bible (©1995)
then it shall be in the day he wills what he has to his sons, he cannot make the son of the loved the firstborn before the son of the unloved, who is the firstborn.

GOD'S WORD® Translation (©1995)
When the day comes for the father to give his sons their inheritance, he can't treat the son of the wife he loves as if that son were the firstborn. This would show a total disregard for the real firstborn (the son of the wife he doesn't love).

King James Bible
Then it shall be, when he maketh his sons to inherit that which he hath, that he may not make the son of the beloved firstborn before the son of the hated, which is indeed the firstborn:

American King James Version
Then it shall be, when he makes his sons to inherit that which he has, that he may not make the son of the beloved firstborn before the son of the hated, which is indeed the firstborn:

American Standard Version
then it shall be, in the day that he causeth his sons to inherit that which he hath, that he may not make the son of the beloved the first-born before the son of the hated, who is the first-born:

Bible in Basic English
Then when he gives his property to his sons for their heritage, he is not to put the son of his loved one in the place of the first son, the son of the hated wife:

Douay-Rheims Bible
And he meaneth to divide his substance among his sons: he may not make the son of the beloved the firstborn, and prefer him before the son of the hated.

Darby Bible Translation
then it shall be, in the day that he maketh his sons to inherit what he hath, that he may not make the son of the beloved firstborn before the son of the hated, who is the firstborn;

English Revised Version
then it shall be, in the day that he causeth his sons to inherit that which he hath, that he may not make the son of the beloved the firstborn before the son of the hated, which is the firstborn:

Webster's Bible Translation
Then it shall be, when he maketh his sons to inherit that which he hath, that he may not prefer the son of the beloved first-born, before the son of the hated, which is indeed the first-born:

World English Bible
then it shall be, in the day that he causes his sons to inherit that which he has, that he may not make the son of the beloved the firstborn before the son of the hated, who is the firstborn:

Young's Literal Translation
then it hath been, in the day of his causing his sons to inherit that which he hath, he is not able to declare first-born the son of the loved one, in the face of the son of the hated one -- the first-born.