As noted in his obituary, he had described himself as "just a chap who messed about in a lab",and "academically not brilliant".
He declined the offer of a knighthood, as he did not wish to be addressed as "Sir". He is quoted as saying, "A knighthood makes you different, doesn’t it, and I don’t want to be different
Sanger said he found no evidence for a God so he became an agnostic. In an interview published in the Times newspaper in 2000 Sanger is quoted as saying: "My father was a committed Quaker and I was brought up as a Quaker, and for them truth is very important. I drifted away from those beliefs – one is obviously looking for truth, but one needs some evidence for it. Even if I wanted to believe in God I would find it very difficult. I would need to see proof."
His father had worked as an Anglican medical missionary in China but returned to England because of ill health.