When you're the parent of a stepchild, you know the importance of a solid family unit that feels inclusive. You take the time to get close to your significant other's child, and you want to feel like a family. As a stepparent, there is the possibility for you to adopt your partner's child.
This process does take away the rights of the other parent, so you may not be able to adopt a child who still has a father or mother present in his life, even though his primary custodian has left the relationship. If the other parent doesn't want to participate in his or her child's life any longer, you can opt to seek adoption, making you the legal parent of the child and freeing the other parent from any parental responsibilities or obligations.
Most states require that you have a criminal background check before the adoption, and sometimes a home study needs to take place, although this is uncommon in stepparent adoptions. The length of time you've been married to the child's parent also matters. If you've been married only a short time, then it's less likely that you'll be able to complete the adoption process.
As the stepparent in this equation, you'll need to get the consent of the other parent as well as your spouse before you can seek an adoption. If the other parent is not in the child's life and has abandoned them, then you won't need that person to give his or her permission to you. An older child must also give permission to be adopted by the stepparent in many cases, so consider this and discuss your intentions with the child ahead of time.
Source: Child Welfare Information Gateway, "Stepparent Adoption," accessed April. 27, 2015