All my friends seem to be having twins these days (below is a picture of my friend Holly's twins, for example) - I wondered if I could use SAS to analyze this twinning trend ...
When I was growing up, way back in the day, twins seemed to be rarity. In elementary school, I knew one set of twins (JoNathan & Johnathan). Another set (Ronnie & Donnie) lived beside my grandparents. And in high school there was Linda & Lisa. That was it - those were all the twins I knew!
These days, it seems like practically all of my friends are having twins! I wondered whether this is just my imagination, or has the likelihood of having twins increased? And, of course, I looked to SAS graphs for the answer!
I did a bit of research, and found that the CDC's National Center for Health Statistics has published some very interesting data on this topic. For example, the data brief "Three Decades of Twin Births in the United States, 1980-2009." I decided to create my own SAS version of a few of their graphs ...
This first graph shows the increase in incidence of twin births in the US since 1980. This shows it's not just my imagination - the chance of having twins has gone up by over 50% since back when I was in high school!
And the incidence of triplet (or more) births has increased even more dramatically!
This bar chart shows that for the older age groups, the incidence of twins has increased even more. And I guess a lot of my friends are in the 40+ age group these days! :)
Well, I'm glad to know it's not just my imagination, and the incidence of twins has indeed increased. Now my new question is why people are having more twins these days? ... Feel free to leave a comment with your theory! (Bonus points if you know what "Wonder Twin powers" are!)