I think a good thing to remember is never ever ask parents what their plans are for back up. I think it shows that you feel guilty. Give them the dates and let them figure out what they do while you are on vacation. In your case however it sounds like you originally said you would only take 2 weeks per year so the parents may feel slightly mislead, however I still don't think it should be a big deal and they definitely were disrespectful. You should change your contract and add more vacation time. I don't think two weeks is enough in this field, I don't know how some of you do it. I take about 4 weeks per year unpaid ( this includes ALL time off including sick days) stats are paid and include easter Monday and December 24-25-26 paid.