Not every male vs female thing is forced by “society” through gender roles. Girls are more nurturing by nature, they enjoy taking care of things. I used to play with my sister all the time, and she had Barbie playhouses while I had action figures and what not, which I preferred as a child. And while she has her dolls cooking in the kitchen, I have my Tarzan action figure climbing up walls and jumping across the roof.
I don’t think there’s anything wrong about guys and girls liking different things. Yeah, it sucks when there are parents that try to deter their children from playing with what they want because it’s “not for their gender”. But for the most part, I think it’s natural.
I can tell you that isn't 100% true. I know as a kid I ALWAYS played with toys market for "boys." Speaking of Tarzan, I had the action figure of him too as a kid that I loved. (img from google but it was this
one.)
I absolutely hated getting baby dolls, dolls, fake cooking sets, and all the like that were marketed to girls in general as kid. They'd always end up being thrown out because I didn't want them. Aside from family outside of my Parents and my Grandparents, they eventually stopped trying to buy me female marked toys because they understood I didn't want them. As well as when I was a kid and even till now, I am _far_ from nurturing. I absolutely despise babies and children. Yes, I've had to watch babies and young children alike and lemme tell you, I'd always get in trouble in the end because I
didn't take care of them nor care for them like was expected because I was seen as a female.
You're also not mentioning how old your sister was by then either though. Because as a baby and onward, we are conditioned to enjoy certain toys because of parents assuming "this child is biologically male/female so they should LOVE these toys." I know in my case, I always took more to my Uncle's toys, action figures, when given the choice of barbies and what not. I also always played with him and played in a similar way to how he did, via being rough with toys.
I would have to find a recording of a study I watched but the study was this: They took a baby girl and baby boy, dressed them up as the opposite gender, and had adults play with them to see how the adults would play with with them. The majority of adults ended up giving the baby girl boy toys to play with because since the baby girl was dressed as a boy, they assumed she was a boy. The same, but opposite reaction, happened with the boy. The babies though? They kept trying to play with all the toys but it was the adults who kept trying to force "boy" and "girl" toys on them. Even so much as to stop the babies /praise the babies from playing with certain toys because the assumptions of the genders that the adults made.