Clearly he tells you that when he wishes to have children, he wants to be their biological father! If you had children with this man, there is no telling, from what you're saying here, whether or not he would adopt yours.

It does not play much a role because he is not ready for kids now anyway. So you are not going to make a big family with him and your kids, at least for the moment. The statement is a little ambiguous, it could either mean that when he does have kids, they would have to be his own biological kids, or he could imagine also adopted kids having his name. If you want to be sure about it, the best way would be to ask him anyway.

What it really means is that his value system and your value system are NOT aligned closely enough for the two of you to seriously consider a meaningful relationship. This doesn't mean there is anything wrong with you. Nor do you need to try to either change him or change your own values. Core values don't change easily. And when they do, it requires considerable PERSONAL effort to do so. People CAN'T change them for another individual. Trying to do so really means you end up forcing them to act in conflict of their values. That ultimately ends in tragedy. You're interested. He's demonstrated at least one serious character trait which CAN'T work for you (I'm assuming, since you didn't come right out and say it). Now the ball is in YOUR court. Is it worth it for you to continue this as a serious relationship? Only YOU can answer that. And before you do, you need to HONESTLY answer the question of whether or not it's worth it based on what I told you about value systems. If you lie to yourself, if you violate or bend your personal values and morals simply to suit someone else, you will likely end up in a very painful relationship down the road. So make your decision wisely.

It means he wants his own kids, kids from his semen. Being a step dad is much harder because it's hard for them to discipline the kids without the mother freaking out and blaming the man for 'yelling' at her kids.