Why is there such a thing as husband and wife?

Scientists believe that couples are caused by the constant movement of molecules. Both husband and wife live for a long time, and male sperm enters the female body and flows all over the body with blood. When female somatic cells run at high speed, they will naturally connect with sperm entering the body. So just like cloning, cells can clone similar individuals. Of course, the sperm in the female body will also bring the characteristics of the female body to the male body, and the longer it is, the more obvious it will be.