Whats the relationship?

[AutomaticGal]

im really baffled buy my situation... are my first cousins really my first cousins or are they my second cousins... basically. i have cousins where their parents and my parents are brother and sister. e.g My dads sister is married to my moms brother. AND ive got normal cousins where one of my parents bro/sis has married someone else. The question is: The cousins where NOT both parents are related to US, are they my first cousins alongside with the ones where both parents are related to us or would they become second cousins?

confusing .. i know...

[jno]

if one of your your parents is a brother or sister of one of their parents you're first cousins. So you're all first cousins. Fancy intermarriage in your parents' generation doesn't alter that. Your children and your cousins' children will be second cousins.

[AutomaticGal]

oooooooooooooooooooooh i get it... CHEERS MI DEARS.

[feebal]

I can see why you're puzzled though AutomaticGal, it's something I've wondered about myself. If you think about it you've got much more DNA in common with one set of cousins than with another. I'd say it probably puts you on the same level as siblings with the double cousins as technically you can usually marry your cousin (ugh) but with yours you're surely too genetically similar?

[saxy_jag]

Noooooo! It's all to with commonality of grandparents. Your parents' siblings' children are your first cousins because you share a common ancestor - your grandparents.

Your cousin's children are your first cousins once removed, because you are of two different generations, ie you are the grandchild of the common ancestor, they are the great-grandchildren - one generation removed.

If you have children, then they and your cousins' children will be second cousins, because their common ancestor is a great-grandparent - two generations removed.

As jno says, complicated marriage scenarios don't change the fact that your dad's sister's (and your mum's brother's) kids are your cousins.

There's a chart about a third of the way down the page on this link that explains it all:

http://en.wikipedia.org/wiki/Cousin