This question is awfully vague but I’m assuming that the OP hopes to have their kid gain some sort of admissions advantage because of what was revealed by DNA testing. In that case I agree with @ucbalumnus. But I think the situation with adoptees is a lot more complicated than meets the eye. And it’s not just a question of whether the kid is obviously of a different race than the adoptive parents.
Adoptees, in my opinion, should not be forever bound by their adoptive parents’ ethnicity or the assumptions made during childhood. It’s natural for adoptees to want to explore their biological roots and want to learn more about where they came from. I’m an adoptive parent whose kid recently did DNA testing. She did Ancestry and 23andme. She’s mostly applying to our in state universities which are auto admit, so for her this is not about trying to game the system. (She was already admitted to several before she even did the testing.) It’s about discovering who she is, where she came from, and how she wants to identify going forward.
I had briefly met her biological mother and maternal grandmother when we adopted her, and guessed that the grandma was probably Hispanic. Over the years D looked in the mirror and also speculated that she is partially Hispanic. I know that what constitutes Hispanic is complicated. It’s not just the percent of what the testing companies describe as Native American or Spanish/Iberian. But what has stood out to us is the names on her list of relatives. By my rough guess 60-70% of the “DNA relatives” have names like Chavez, Garcia, Gonzalez, Moreno, Armijo, Perez, Quintana, Montoya, etc. Names that I would customarily associate with Hispanic heritage. Several of the closest ones (2nd/3rd cousins) have public family trees that show a presence in New Mexico going back generations.
She wants to identify at college as Hispanic and join organizations like the Hispanic Engineers group. She hopes to eventually meet biological relatives although so far our efforts to reach out have not received a response. But the bottom line is that I feel strongly that she is entitled to expand her identity beyond that of her adoptive parents and beyond the assumptions made by others when she was a child.