How are they related?

Question: How are they related!?

My grandfather and his son got married to two sisters!.
What relation does it make their offspring kids to one another!?
Now the grandchildren from my grandfather and my uncle got married!?
How are they related!? that is my grandfather grandkids and my uncles grandkids!. Help!!!!Www@QuestionHome@Com

Best Answer - Chosen by Asker:

The grandfather's new children are half-brothers and sisters to the son!. The son's new children are grandchildren to the grandfather!. The children are aunt/uncle to niece/nephew on their fathers' side and first cousins on their mother's side!.

The grandfather's new wife is step-mother and sister-in-law to the son!.
The son's new wife is daughter-in-law and sister-in-law to the grandfather!.

For simplicity I'd think the grandfather and son will continue to call each other whatever they usually do!. The son and wives will call each other by their first names and the kids will describe themselves as cousins -- because it's easier!.Www@QuestionHome@Com

Here is a great article about this subject:

http://www!.ancestry!.com/columns/george/0!.!.!.

Here is a online program just for you:
http://www!.searchforancestors!.com/utilit!.!.!.Www@QuestionHome@Com