Sexual Dimorphism Denial

The UUWorld Summer 2016 “Families” page suggests that leaving gender specific pronouns out of our speech will ensure fair treatment for all genders. According to the article, girls and boys would not be limited by their gender in such a culture.
Let’s examine a historical example of this thesis.   The Chinese language does not have gender specific pronouns – “he” and “she” translate as “zee.”   Nevertheless, for a thousand years in China, girls were subjected to the cruel and crippling practice of foot binding.  Deliberate disabling is limiting, to say the least. Foot binding was outlawed for the first time in 1912, but continued in the remote provinces.  There are a few surviving elderly women with bound feet, although the last store selling “lotus” shoes closed in 1999.
Due to Western influence, written Chinese began to distinguish pronoun gender in 1917  even as the foot binding custom was decreasing.  It seems gender specific pronouns are not linked to gender-based oppression.
Politically correct or not, a few plants and most animals, including humans, come in male and female, a phenomenon called sexual dimorphism, the technical term for gender binary. The female provides quality gametes; the male provides a quantity of gametes.  The reshuffling of traits at fertilization helps the organism adapt to changing environments.  For instance, bananas, which reproduce asexually, were predicted in 2003 to become extinct in ten years.   https://www.newscientist.com/article/mg17723784-800-going-bananas/
Animals have sex; people have sex and gender – the feeling of being masculine or feminine.  Usually sex and gender coincide, but if they don’t, individuals like Ben (trans boy featured in “Families”)  should be treated with kindness and fairness.  Nobody should be forced into doing something because “boys don’t” or “girls have to.”
Many years ago I met a young person whose sex I could not determine.  I felt disconcerted at first.  How should I relate to this person?  Then I realized since I wasn’t dating this person what did it matter?  Maybe at some future time when everyone can be bisexual and attraction depends on the personality of their date, physical sex won’t matter except to get sperm and egg together.
Pronouns are irrelevant, but denial of sexual dimorphism by not using “he” or “she” is as unscientific as climate change denial.