This seems like terrible advice to me. "Men with daughters are less sexist" and "Men whose wives work are more sympathetic to working mothers" are extremely vague, only loosely correlated to what you want to know, and pure anecdata. Someone could make up an equally plausible counter-argument (say, "men with young daughters are more likely to infantilize female coworkers"), but it would still just be story-telling.
If you want to know how your possible-future boss treats the women he works with, how about, "Have you had any women report to you? How'd that work out? Were there conflicts, and if so, how did you resolve them? Do you think they'd be happy to work for you again?" I'd be happy to answer those questions. Asking what my wife does for a living will get you a very awkward, "Er, let's get back to the interview."
If you want to know how your possible-future boss treats the women he works with, how about, "Have you had any women report to you? How'd that work out? Were there conflicts, and if so, how did you resolve them? Do you think they'd be happy to work for you again?" I'd be happy to answer those questions. Asking what my wife does for a living will get you a very awkward, "Er, let's get back to the interview."