There is always adoption.
As a child who was adopted, I can only tell you that I love my parents like they birthed me, and I've never suspected any sort of different between out relationship as anyone born of blood.
At 16 I discovered I had a biological sister that was 2 years younger than me who was also adopted. She was adopted into a loving family same as me, and we both grew up to be very intelligent and respectful people.
Currently my wife and I have no plans to have children (we've been married for 11 years), but if we ever did, I'd go with adoption.