There is nothing natural about 1950s gender stereotypes, they are the product of societal and structural misogyny

• The Oxford dictionary definition of natural is ["existing in or derived from nature; not made or caused by humankind"] (https://languages.oup.com/google-dictionary-en/), and the definition of stereotypes is ["a widely held but fixed and oversimplified image or idea of a particular type of person or thing"] (https://languages.oup.com/google-dictionary-en/). This suggests that Stereotypes are derived and enforced from societal norms and ideas, thus made by humankind. This therefore is not natural or derived from nature, thus there's nothing 'natural' about the traditional gender stereotypes of the 1950s
• Much of history, especially since the improvement of Women's rights have proved the stereotypes wrong

The gender stereotypes of the 1950s were reinforced by popular media, making them seem “natural”, but they actually just reflect deep-rooted sexism.

• Companies embraced the gender stereotypes of the time, even going so far as to center their advertisements around them. For example, large corporations such as Budweiser, Hardee’s, Heinz, Van Huesen, and Chase & Sunborn Coffee show blatantly sexist scenes in their advertisements. These ads were so commonplace that the gender roles they enforced were often perceived as normal. Just as we become desensitized to certain things when they are exposed in media today, the same happened back then.
• This does not excuse this behavior, but does show how intrinsic sexism was just a few decades ago. Sexism still remains a huge problem today, but there would be much more backlash if an ad such as the ones above were published in modern times.
• The gender stereotypes of the 1950s were heavily enforced, not just through advertising, but through social expectations and, unfortunately, domestic violence. Women were expected to submit to their husbands, which harms the women themselves, but also made no room for anything that didn’t fall into the heteronormative standard of the time.
• Nothing is natural about the gender stereotypes of the 1950s because they had to be so strictly enforced. Any straying from the norm could lead to consequences for whoever tried it, meaning there was no "natural" order of the sexes, but rather a socially created order.

You are saying "1950s gender stereotypes" like it has a categorical definition? If you instead mean the normal sex roles of the majority of human beings throughout all history and across the world today then I think I understand what you mean.
In that case then yes they are most obviously natural.