DEAR MISS MANNERS: I am a single father. I am not divorced; I am not co-parenting. It is just me and my son.
Many people I meet cannot seem to grasp the concept, and I am constantly asked invasive questions. Many of them are about my former wife or girlfriend (no such person exists). I am sometimes asked about my son's origins -- traditional birth, adoption, surrogacy, etc. A surprising number of times, I am asked the highly specific question, "How often do you get him? Every other weekend?"
When people encounter a single mother, no one ever asks, "I see you have four children. How many different fathers?" or "Do the fathers pay child support or are they deadbeats?" It's ludicrous.
GENTLE READER: Don't be so sure that single mothers are spared this intrusiveness. Or any parents, for that matter. Or just about anyone else, as we have a pandemic of rudely expressed nosiness.
So Miss Manners believes it is useful to have a response that means, but does not say, "None of your business."
In this case, start with a firm "It's just him and me," which can be quietly repeated as necessary. And the answer to where you got him can be "The stork brought him," or "From the cabbage patch," or "Surely you know where babies come from."