Is it possible to see if two people are related threw a Y-chromosome test if...?

Question

Alright, i was wondering if it is possible to use a Y-Chromosome test to see if a guy and girl closely related if you use the girl's half brother (Since they have both the same father) and also, is it possible for the test to be accurate if the girls father's mother, or grandmother is the reason for the possible relationship and since the guy's father is the relationship. Would this be an accurate test since the Y-chromosome is only passed from father to son?

Or also, could i be looking at the wrong type of DNA test for this situation. Any help would be very much appreciated. Thank you.

Also, to help with clarification. I am wondering what style of DNA test i would need to find out how closely related i am to a girl that is possibly related to me. We need to find out how far related we are for several different reasons. So, as i said before any help would be very much appreciated. Also, a family tree will not work since we need scientific evidence.

Answer 1

The Y-Chromsome has to be between sons of sons of sons . . .

If you are looking for what the DNA company delicately called "hidden adoption or infidelity", there is probably something you can do, but I'm not an expert on that. You might write to a DNA testing company and ask. I used FamilyTree DNA, but there are others.