Of course, the sex is the part of human as you admitted. Having a kid is definitely the product of sex. Imagine a strong undefeatable nearly-immortal guy getting killed just because of his "desire to have family"
So now you saying "Having a kid is definitely the product of sex." see how you switched your argument? That's exactly what I was saying, a kid is a product of sex but NOT NECESSARILY a product of lust. Good job.