It's important to realize that this pushback you are seeing is not because people think girls should not play with chemistry sets. It's because, in point of fact, there _is_ a cultural force out there that exists, that insists that boys and girls are blank slates and if not for antiquated belief systems, all jobs or interests would be split 50/50 across genders.

They are pushing back against the pressure to conform to this new dogma, not that they would deny any particular girl access to a "boy's things".