Adoption is a process whereby a person assumes the parenting for another and, in so doing, permanently transfers all rights and responsibilities from the original parent or parents.
Being adopted is a major theme on Smallville.
- Clark Kent - Adopted by Martha and Jonathan Kent
- Lana Lang - Lana was adopted by her Aunt Nell.
- Lucas Luthor - Put up for adoption by Lionel Luthor
- Tess Mercer - Put up for adoption by Lionel Luthor
Apocalypse - Alternate reality where Clark's ship never reached Earth
Earth-2 - Alternate reality where Clark's ship reached Earth, but Clark was discovered by Lionel
- Chloe: (about the family tree project) There's just so many variables to take into account. Like, what if your mother abandoned you? Is that branch of your family tree technically cut off?
- Lana: Yeah, and what if your biological father comes back into the picture? Which family do you claim?
- Clark: What if you're adopted?
- Pete: Okay, I get the point but, is it my fault that I'm part of a nuclear family? Is it? Later.
- Chloe: Unfortunately for the rest of us, our nuclear family was nuked years ago.
- Season Two, Rosetta
- Martha: I want to help this boy as much as you do, but I took an oath to uphold the law.
- Clark: All he's trying to do is find his mom!
- Martha: I know, but we have to go through the proper legal channels.
- Clark: Was it legal when you forged my adoption papers? I'm an illegal immigrant, Mom. You've been harboring me for over seventeen years!
- Season Six, Subterranean
- In three separate times, the Traveler has been adopted by people of Earth. In two timelines, Lionel Luthor was able to adopt the traveler: in the reality where Kal-El's ship never arrived, he adopted Kara and in another reality where Kal-El's ship did arrive, he adopted Clark Luthor.
- In the two timelines where Lionel adopted the Traveler, death and destruction soon followed as Lionel raised the Traveler in much the same way he raised Lex.
- In the timeline where the Kents adopted the Traveler, Clark Kent became the protector of humanity.
- This highlights the emphasis in the Smallville universe placed on parenting.