Where Adam and Even the only people God created at the beginning?

Funny, I was asking myself this very question a week ago. But after much searching and reading, I have come to the conclusion that God created only Adam, then Eve, in the beginning. Remember, Adam lived 930 years. Lots of children can be born in all those years. Back then, they married their sisters. It was acceptable because Adam & Eve had a pure bloodline which caused no defects. But this practice stopped when Moses got the statutes from God. This practice was no longer acceptable because of defects, illness and such. It's biblical if you care to search it out as I did.