If you were adopted or know that you had a sibling who was adopted, you might be searching for that brother or sister. Having a parent's name is a good starting point for your search. Although the search may be a long one, the reward of finding a sibling you may never have seen is more than worth the effort.
Head to the Courthouse
Check local court records to look up adoption cases with your parents' names or someone with the same last name to see if you can find information regarding an adoption through your county or your parents residential county.
Research Online
Visit websites such as Adoption Reunion Registries to seek siblings who may have been adopted or put into foster care. Also, search Facebook, Twitter, and other social media sites for people around the area with the same last name as your parents. Send messages to people who seem to be prospective siblings and ask -- if they don't know, perhaps they have some helpful information that can steer you in the right direction.
Talk to the Family
Question family members. While some relatives may not say much about the situation, others may share any information they have. Talk to cousins, aunts and uncles to see if anyone has any leads for you to start from.
Check with the Adoption Agency
Call the adoption agency that handled your adoption, if this was your situation, to see if you had other brothers or sisters who were adopted at the same time or through the same agency. The agency may be able to give you a name or birth date of your sibling to get you started on your search.
Hire a Professional
Consider using a private investigator. These can be expensive, but if you have some considerable information on your siblings, an investigator may be able to locate possible matches.