DNA Lady
When adoptees (for lack of a kinder word) go in search of their biological parents, a DNA test may be a useful tool depending on what you're trying to accomplish.
If you have been lucky enough to find someone who you believe to be a biological relative, we have DNA tests and probability calculators to give you an idea of the value of evidence DNA testing can provide. For example, if you are a female and find someone who is supposed to be your half sister (you shared one biological parent) and we can collect DNA from just you and the alleged half sibling, a DNA test could return limited support of about 90% probability of relatedness. Although the 90% number is not enough evidence to be used in a legal process, if there were no "relatedness" the number would return at 0% - so at least you will have an idea of whether there is some biological matter shared between you and this "alleged half sibling" and you can move onto to other relatives in that siblings family line.
Just to continue to give an adoptee more statistics on this subject, suppose you are female and you find a man who is the brother of your alleged father. An avuncular test could return evidence with moderate support of 92% probability of relatedness. And as has happened a number of times, I get phone calls from a woman who says that the father of her child is deceased but she wants to prove paternity. We can collect the deceased alleged father's mother, father, sister or brother and provide evidence is support of the relationship. It is a matter of testing as many of the available relatives as possible.
The idea being, that whoever you find in your search for a biological relative, your local DNA collector probably has a test that can determine if there is a biological relationship between you. Some DNA collectors offer biological reconstruction where up to 5 people are tested at one time and a biological family tree is created - if there is matching DNA among the 5 people. You may find a loosely knit family with knowledge of family history but have never decided to confirm or research the stories. DNA testing allows you to rule out rumors and confirm relatedness.
On the other hand, if you have not been able to find biological family members and you just want to know what your ancestral map contains, Genealogy and Ancestral DNA tests are also offered by your local DNA collector. Look for my blog entry that explains all 18 haplogroups of the world - do you know which one you may belong to? Perhaps that's your starting point and from there you can seek out possible family members based on the haplogroup information. An example would be if you are a man and your haplogroup returns as part of the Haplogroup B and Haplogroup I - then iit would make no sense to go testing people who are obviously from Haplogroup O. An additional feature of the ancestry testing, is the ability to connect via email with possible genetic cousins/relatives. People who are already in the database and those who may enter the database in the future. You and the "biological relatives" have to authorize the connection, but as the database of ancestral researchers grow you are bound at some point to find a biological relative; however distant.
Some setbacks, if you are female - you can really only test your maternal ancestral heritage because you do not carry the Y-Chromosome of your paternal heritage - it is actually destroyed at conception. However, a male can test for both his maternal and paternal lineage via Y-Chromosome and mtDNA testing because the male carries by Y and X chromosomes. Keep in mind, ancestral DNA tests are not considered legally admissible in court for matters of Estates and Wills.
