Is blood thicker than water?

I've been thinking about this quite alot recently and it's always presented me with questions, not only for my closest family members but extended kin too. Do you believe that because of your genetic predisposition you owe your family some form of allegiance, and how far does that allegiance extend? To second cousins once removed? I find the whole thing very interesting, particularly since you think of how the family dynamic within society has wilted over the course of the last 30 odd years. Where do you stand on it? Is family the be all and end all for you, and where do your boundaries lie in terms of what you'll do for them, and which ones are deserving of your complete trust? I'm so talking like a Catholic Irishman by the way. lol.

I am normally rather trusting. 
Trust is like an eraser, every time someone breaks my trust it just gets thinner and thinner. 
It's hard to trust people because of how much trust has been broken so far in my life.