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Vasectomy question?

I'm 35 years old and had a vasectomy about 7 years ago. My wife thinks she might be pregnant and I know there is a small chance my vasectomy could have failed. She asked if I would want a paternity test done, I told her that I would only want one if I had a test done and was shown to be negative for sperm. She told me that that wouldn't matter cause it could have grown back in a way that only allows sperm through sometimes and not all the time. Is this actually possible?

Male | 36 years old

3 Answers

UrologyUrologist
Yes
A semen analysis would let both of you know if the vasectomy was successful or failed. If there still is sperm, it would be consistently positive. Obviously, if your wife only had sexual relations with you, a paternity is not necessary!
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Generally speaking, the risk of a vasectomy failing is approximately 1/1000. If you have a negative sperm test shortly after a vasectomy, the long-term risk of failure is reduced to approximately 1/2000. If a vasectomy fails, then I would expect you to have a positive sperm count, whenever you did the test. The vas deferens will either be patent or not. I don’t believe it would be intermittently patent.