Chimpanzees play with "dolls"

When I was little, I played with a lot of toys handed down from my older brother: Pirate ships, Playmobil armies, cars, but my grandmother also provided me with three American Girl dolls. If you don't know about these, they are large high-quality girl-dolls from different periods of American history with plenty of historically-accurate outfits and accessories you can buy. My favorite was Kirsten, the Swedish immigrant.

There's an open debate about why girls plays with dolls and boys play with trucks, whether this is positive or negative behavior, and whether this is natural or socially induced (why, for example, did grandma buy me dolls and doll-dresses and doll furniture instead of toy microscopes and model airplanes?)

In 2002, a study on Vervet monkeys presented the possibility that these gender-roles are more natural than many would like to admit. In the study, female vervets preferred "feminine" toys like dolls, while males went for trucks and cars, with no clear difference in "gender neutral" toys which I guess are like blocks or something. (Click for article)

HOWEVER! Field data collected from wild chimpanzees in Kibale National Park suggests that juvenile chimps play with sticks in a way very similar to how human children play with dolls, cradling them and building nests for them to "sleep" in at night. Furthermore, both males and females play in this manner. (HERE) Does this have implications for human behavior?

Looks like the debate is still open to interpretation.