&gt; Why does everything for girls have to be pink?<p>That&#x27;s fairly recent. It wasn&#x27;t until the early 20th century that blue and pink started being promoted as gender identifiers--and it was pink for boys, blue for girls. It stayed pink for boys, blue for girls until the 1940s, and then the pink for girls, blue for boys convention took hold.<p>From the &#x27;60s through the mid-80&#x27;s the trend was toward gender-neutral clothing for kids, due to the rise of feminism. The style of feminism at this time had a strong anti-femminine bent.<p>The next generation of feminists took a more accepting approach to femininity, accepting that a woman could be the equal of a man and still also want to be feminine. Marketers picked up on this, and started pushing the blue means boy&#x2F;masculine and pink means girl&#x2F;feminine because having different categories leads to more sales (if a family has children of both sexes, they need to buy two sets of baby things instead of just passing the first baby&#x27;s hand-me-downs on to the second baby). Hence, the spread of blue for boys, pink for girls beyond clothing to things like cribs, strollers, room paint, and so on.<p>Here is a nice article on this history of this: <a href="http:&#x2F;&#x2F;www.smithsonianmag.com&#x2F;arts-culture&#x2F;when-did-girls-start-wearing-pink-1370097&#x2F;?no-ist" rel="nofollow">http:&#x2F;&#x2F;www.smithsonianmag.com&#x2F;arts-culture&#x2F;when-did-girls-st...</a><p>&gt; I feel like, if we got rid of all these false associations, the difference between genders would be minimal, and that would make the sorts of problems discussed in the article a lot more manageable<p>There would probably still be some significant differences. Nearly every other mammal has significant sex-based [1] behavior differences, including primates. It would be astounding if humans did not. There is research that indicates that very young children do have built-in preferences for certain kinds of toys and that these preferences are different for boys and girls, and there is research that finds these same preferences in some non-human primates.<p>For instance, studies in two different monkey species found that girl baby monkeys preferred to play with dolls more than with trucks, and boy baby monkeys preferred the trucks over the dolls. See <a href="http:&#x2F;&#x2F;www.livescience.com&#x2F;22677-girls-dolls-boys-toy-trucks.html" rel="nofollow">http:&#x2F;&#x2F;www.livescience.com&#x2F;22677-girls-dolls-boys-toy-trucks...</a><p>Researchers looking into these preferences in human babies have found that they correlate with sex hormone levels. Boys with higher testosterone levels tend to have stronger preferences for &quot;boy&quot; toys. Girls with congenital adrenal hyperplasia (a condition that causes them to experience high levels of androgen in the womb) preferred &quot;boy&quot; toys, lending more credence to the theory that hormones are involved. (See previous link for more on this).<p>[1] I&#x27;m saying &quot;sex-based&quot; here rather than &quot;gender-based&quot; because when talking about more than just humans we need to stick to things we can externally observe. Since sex correlates very highly with gender in humans, this substitution works for most humans.