A few years ago I took American History 101 at a public university in the US. The professor covered 1800(ish) to 1900ish. My professor was a t.a. working through the doctorate program, and I am almost certain the syllabus was his own. He basically taught the course around different aspects of sex throughout that 100 years. For instance in week 1 we talked about different states sex laws as a result of the religion that founded that colony/state. In later weeks we discussed how sex affected the Industrial Revolution (to be honest I can't remember what the affect was supposed to be).
Is this a common way to teach this course? He is the only person I have ever heard address history in this way (it was terrible but that may have been more about him than the subject matter). Did sex really affect American History that much?
Edit: The course book was Reading the American Past Vol. 1.
in history, we generally have to delimit the way we teach/study/write.
the course was probably subtitled something like: "Sex and Sexuality in American from 18XX to 19XX."
by doing this you can uncover different ways of looking at time periods, social phenomenon, and historical events. for example, one could teach a course entitled: "Sexuality and the Making of America: From Colony to Country." it could investigate the ways in which sexual identity, restrictions/perceptions of sexuality/sexual acts, and popular and/or official discourse on sexuality affected the way the country operated and was conceived of. if you don't look for new access points into eras, you end up with survey courses that attempt to cover (often too much) general context and basic arguments.
On the one hand, using sex as a critical lens is not particularly common, at least not in my experience. My first reaction is that it reeks of an attempt to curry favor with undergrads through salacious content. But the flip side of that coin is that, like /u/rustyarrowhead says, it can be a very effective strategy to use one over-arching theme to help introduce students to a variety of concepts in historical studies. For example, I can see a survey of nineteenth century America through sex touching on religion (as your course did), feminism, the experience of various groups in the Civil War, slavery and relations between American Indians and White Americans. All of which are topics I would want to introduce in a survey course, anyway. So I don't think it's a good idea to dismiss such an approach out of hand, but I wouldn't want to try it given the generally litigious nature of today's college students as well as the potential for rendering your subject matter too unserious and therefore not actually teaching anyone anything.