If all you are expected to do is to shoot - P&S type - shots, then yes that can be an issue. However, if you can get to the point where your family does not "pose" for images and just gets used to you being around and you can get flash less intimate images of family - which just might turn out to be real gems - then that is something to work on.
Sometimes photography is not all about "fun and a hobby" sometimes it is about drudgery and is as boring as all h*ll. If you are not interested in photo sessions - because you have the "big" camera and a real (read paid for pro) photographer is expensive, sit down with the relations and explain that if you do this - you will charge them and write up a contract. Sometimes relations decide that you are there for their convenience - just set the record straight - doing formal shoots is work it is not free.
Just be honest, if you do not want to do the shoot - say so. If you want to do it, to learn - get experience - get a reputation outside the family etc., then sit down and write up a formal agreement where you get paid - real money - for doing the deed. Be assertive but not hostile and make sure that you are not being the patsy here.
As for my close family, they literally leave the room if I get out my camera. The last picture I took of my wife was on our vacation in 2006 and I have well over 5,000 images on my K10D that has never taken an image of her. My last picture of my son I took in 2007 as he was sleeping in a chair - otherwise I would have never been able to take the shot. You might want to investigate this book
Joel Sartore Photography - Products - Nebraska: Under a Big Red Sky Joel is a great National Geographic photographer - his book should be very good. I would love to be in the situation where I could take out my camera and take intimate images of people - family would be a good place to start, but formal shoots? Nah - I would charge them an arm and a leg, plus I would get model releases, get paid up front and plaster their images all over.
The Elitist - formerly known as PDL