I've had no problem telling my family - my mom, brother, both sets of grandparents were supportive of my decision. The only one that "bingoed" me was my dad - I think that he had his heart set on grandchildren...and now, since my brother is gay, and I've decided not to have any, he seems a bit disappointed about it. I was amazed that he'd just write my brother off like that...I've met a few gay couples that were parents...and terrific parents at that. Although, it would surprise me if my brother became a parent at all...his temperament isn't the ideal for a parent to have (impatient, stubborn, short fuse).
My husband's family, however, is a different story. His brother and sister-in-law know, but he's kindly asked them not to tell ANYONE else - not his sister, not his uncle, and ESPECIALLY not his mother. I hate having to dance around it, but hubby is certain that if his mother learns of her favorite son's vasectomy, it will break her heart. She has enough health problems as it is - this revelation would just aggravate them. If hubby's sister is told, then the sister will definitely blab to step-dad or uncle, so we've decided to treat her like a mushroom: keep her in the dark and feed her on sh*t.
I assume that hubby's mom felt like she'd be surrounded by the children of her 3 offspring - but she's only gotten 2 so far, by hubby's brother. Hubby's sister has been rather adamant about avoiding motherhood, so it looks like two grandchildren is all she's going to get. It would just be CRUEL to take that hope away from her.
I just hope that she doesn't get aggressive with trying to persuade me to have kids. I, like my brother, have a short fuse also, so I might spill the beans without intending to. Glad I only go over there once every six months, with hubby, for the obligatory visit. :P