(Al-Vaqia) 56 : 58
أَفَرَأَيْتُمْ مَا تُمْنُونَ
Have you thought about what you emit?
"About what you emit" means about the sperm/semen and ovum you ejaculate. It is the Creator Allah who forms blood from the food the father and mother eat, and from the blood, the semen and ovum. See explanation 4: 1.