It was several years ago (15), but I actually took the time to read "the Bell Curve" and even to find some of the actual twin studies that tend to be cited in the discussions. Those I found rather underwhelming - for example the sample sizes tend to be low and not very comparable, and sometimes they are clearly exaggerated. For example one mentioned twins who gave their kids the same names and wore the same clothes even though they didn't know each other.

Over the years I have read a lot of articles on the subject - as did many others, I guess, it is a popular subject after all.

I'd say it took me more than a few seconds to come up with my example.