"I don't mean to offend but what is the difference to you that the child is genetically yours? why not adopt?"

This might be an unpopular answer, but it makes all the difference in the world. I want my family line to continue; I want my parents and grandparents to see physical features and behavior quirks in their (great-)grandchild that I haven't even noticed.

It's a primal urge and I can't explain it rationally except to say that I'm human and no exception to what we are hard-wired for.

Some try to take a fundamentally 'rational' approach to life, or view it through the lens of cost/benefit, especially fiscal cost benefit. In fact I have some friends who do not want children simply because they will cost too much money.

This brand of rationality is very alien to me. It makes all the difference in the world if the child is genetically one's own child. It is not a toy or a cat. It is an emotional extension of your own being that culminates in having its own identity. It is both you and not you. I fear that if you cannot intuitively grok the difference that it makes, there is no 'rational' way to convince you that it matters.

Adoption is expensive, difficult, and often heartbreaking. I hate it when people casually throw out adoption as a solution without understanding anything about the process.

There are more parents willing to adopt than children available for adoption. While there are some children still awaiting immediate adoption right now, many of these children have very very specialized needs which (I'd guess) most people would not be able to handle because they do not have the right training.

There is a moral answer to that question and there is a primal answer to that question. Several, in fact.

I wanted my kids to be my own genetically so I can better relate to them (and their genetic quirkiness. Tourettes runs HARD throughout my family) and give them some good insight to family diseases to be aware of.

I agree and am surprised by the number of “I want the same genetics”. Its good to hear an alternative perspective.