I disagree with some of the opinions. I absolutely love when my wife goes with me on jobs. We get that work time together, we can break for lunch together, we work well together, and she contributes ideas to me that I hadn't thought of at times. She says I think too complex and sometimes simple is the best way. Sometimes she's right on that.
Some of the opinions here make sense though. Roofing is a physically demanding job, be it carpentry and sheathing, or shingles, either one demands strong upper body strength and stamina to last the duration in the heat or cold. The plain fact is, most women don't have that, they are physically different, as in usually weaker, and that's all there is to that. Also, not every couple can work together, but that is more of a case by case basis instead of a general rule to apply broadly.
Oh, and the one about the dishes, laundry, cleaning, and dinner?? Really?? I can't believe that was put in print.