Laws vary from place to place and state to state. In most places it would not be allowed. After all your parents are her grandparents. In the UK, the Law regarding Marriage and Divorce is that you can't marry a close blood relative, but you can still marry a relative (anybody outside of your immediate family). Correct this if it's wrong, but your niece is a close blood relative (your sibling's child after all), so it wouldn't be allowed. You can, however, marry your cousin.
If you mean niece, no. That is illegal.
it's like your 3rd cousin
yes
Your grandfather's brother's grandson is your great uncle's grandson. The grandchildren of great aunts and great uncles are your second cousins.
Your aunt's grandson is your first cousin, once removed. Whether or not you can legally marry him depends on the laws of your country, province, or state.
Your aunt's grandson is the son of your First Cousin and is therefore your First Cousin once removed Ref: http://freepages.genealogy.rootsweb.ancestry.com/~gentutor/chart.html
No, Brother-Sister relation
Your son and your aunt's child are first cousins, so your son and your aunts grandson (the son of your aunt's child) are first cousins, once removed.
it is unknown as of right now, but her love interest is Jagged Fel. it is likely that they will marry, resulting in the force-sensitive Emporer Roan Fel in the Legacy comics, nearly a hundred years later. (he'd probably be a grandson or great-grandson)
Yes, it should be, it is not considered incest because it is not by blood. You are marrying your aunt's HUSBAND'S daughter.
The possessive form of the plural noun aunts is aunts'.Example: My aunts' names are Alice and Anne.
Yes, Dwight David Eisenhower II married Julie Nixon.
Yes, although in that relationship there is likely to be a very large age difference, since that person is of the same generation as your grandparents.