Almost 20 years ago, my brother was served a court order to take a paternity blood test together with two other alleged fathers to a baby girl that they had supposedly fathered. One of the other two guys is a relative of ours while the other is his best friend. However, my brother was the only one who went in and received a result of 93.3%. The girl is now almost 20 years old and looks identical to one of the other two guy's daughters which happens to be a distant relative of ours. Anyhow, would it be possible IF the other two had gone in that one of them might get a higher percentage than my brother?

None are exactly l00%, 93.3 is about as good as it gets.

I have an adopted son, when asked, he looks much more like me, than my real son.

Looks mean nothing, esp since family appearance can go with the gene and DNA. If they looked just like a non family member, that may be more suspect.

But the issue should have been fought in court 20 year ago, and a demand of other people be made in court.

And why after 20 years does it matter. He should have been a father to the child all these years and would not want it changed if it was.

And there is little legally to do anyway.

But yes very reliable, and doubtful if this is not his

The laws vary from state to state.
It is required 99% in some states, it is required95% in another states.

Its harder to get accuracy when they are distant relatives

Well, I guess because he was still young and immature and didn't know what else to do. He panicked and moved out of state because he wasn't serious with the girl to start with so it was a one-night-stand thing. So you could say he's a jerk because he never wanted to take care of her nor the mother. And then they started deducting half his pay check without knowing if it's really his or one of the other two. This just came up again when his wife saw his "alleged" daughter on Facebook and confided to me about it. I guess they want to look in to it again and IF it's not his, they can file a law suit with the state of Washington. But if it is his, then, his kids need to know that they have a sister out there.

Its too late to file a suit. And his kids should have been told about the girl long ago.

And if the parties are willing, they can of course do a DNA test now,

I don't know about 20 years ago, but I believe that now DNA testing is usually done with saliva, not blood.