Barbie wasn't always a single girl on the town, when she was growing up she had two siblings!
Tutti Roberts and Todd Roberts were Barbie's younger twins. They first showed up on the scene in 1966 and were available in the US and Europe from 1966 until 1980 when they were discontinued.
Though Todd was reintroduced in 1991 as part of the wedding party for Barbie's best friend Midge Hadley. Almost like a brother who was returning after a long family feud! Though what happened to Tutti, we don't know. She probably married out of the country - maybe a French Action figure?
Tutti and Todd originally looked a lot like small school children and had very flexible bodies. so you could bend them all over the place.