I know I'm not alone in that sentiment -- just look at all the research that goes into studying twins, the movies about twins, and the articles about twins. I read two such articles today.
The first was on the BBC in an article about how twins are more likely to occur with older mothers. Researchers found that older women are more likely to produce more than one egg a month, resulting in more multiple births. This process initiated by Mother Nature, according to researchers, is very similar to what doctors do with in vitro fertilization.
The second article was in my home-town paper, the Chicago Tribune, about how increasing numbers of twins and multiple births could someday change society and politics. The article points to anecdotal evidence that because twins are forced to share so much while growing up, they tend to become more sensitive to the needs of others and interested in issues of fairness, such as welfare and education. There's a lot more to it, and it's very interesting reading.