Wife wants me to get a vasectomy but wouldn't it be easier for her to just get her tubes tied after this...?

My wife is 5months pregnant with our 4th child and we have both decided that this is it and that this will be the last child. Well anyways she wants me to get a vasectomy but wouldn't it just be easier for her to get her tubes tied after she has this baby? I honestly don't feel comfortable letting some doctor take a knife near my and to be perfectly honest since were not having anymore kids she might as well have her tubs tied. Because why take a chance? But then again i have been thinking about telling her she should just get on some Birth control instead of either of us having to screw with surgery's and crap. What should i do? Wouldn't it be just as easy for her? I mean what does it matter why can't she do it, it instead of me having to do it. Gah sometimes women are so very manipulative in the back of my head i feel like she does want more kids she should do it and i know women are going to bash me and call me a jerk and chit. But i don't care this is kind of where i draw the line with myself.