Can you date your brother-in-law's nephew?

Answer 1

You can date anyone you want.

It is when you get more intimate physically that questions begin to arise. Having sex with an uncle is generally considered to be incest, is frowned upon, and is illegal in many locations.

Answer 2

It depends on how you define "okay" (and possibly on how you define "date").

First, the legal issues: It is legal in many places (and in some cultures even regarded as desirable) for first cousins to marry. Your great-uncle's children are your first cousins once removed, so they're related to you more distantly than your first cousins are.

Scientifically speaking, the odds of an unfavorable genetic combination are higher between related individuals than between two randomly selected members of the general population. By the time you get out even as far as "first cousins", the difference in the risk is pretty small, though it's still present, and if your family has a history of colorblindness (or something worse) then it's something you should definitely give serious consideration to.

Finally, there's culture to consider. In some places (including most of the US) you should expect a fair amount of negative reaction (well out of proportion to the actual risk, and regardless of whether it's technically legal or not) about dating someone that closely related to you.

Answer 3

Legally yes there are no laws against it. Although your family might have some issues.

In case you're interested, the entire 18th chapter of Leviticus, the 3rd book of The Bible, lists who the followers of Moses were not allowed to "date", and most of what our society dictates on the subject is based on that chapter.