Psalm 139:13, 15, 16

“Your eyes saw even the embryo of me, And in your book all its parts were down in writing, As regards the days when they were formed And there was not yet one among them.”

Scientists now know that the genetic code is primarily contained in the “genes” located in the nucleus of the fertilized ovum. God, who designed the pattern for mankind, can also know beforehand the specific physical and mental traits a child will have by inheritance.​—Compare Genesis 16:11, 12; 25:23; Romans 9:10-12.