4 “Haven’t you read,” he replied, “that at the beginning the Creator ‘made them male and female,’5 and said, ‘For this reason a man will leave his father and mother and be united to his wife, and the two will become one flesh’? 6 So they are no longer two, but one." -Jesus, Matthew 19
Jesus is rebuking some chauvinist men who are leaving their ageing wives to chase after hot younger women. Their argument was that under Moses there had been a provision for divorce. Jesus replied that they had been misapplying Moses and used Moses own words to prove it. In fact he used Moses' foundational teaching of the early chapters of Genesis to make his point. So what does the opening of Genesis to which Jesus' points have to show us about God's intention for gender?
In the beginning God made a colourful world. He could have had a grey one, but he made distinctions and thus variety and excitement. He separated night from day, sky from water, water from land, etc. Then at the climax of creation God reaches down and makes man... but not just man. He puts a fundamental divide into humanity when he didn't have to. As Jesus quotes Moses, God "made them male and female". Why did he do that? In keeping with how he made the rest of creation he made variety. Wouldn't it be boring if we were all just generically human? Like if the sky ad the water just murkily merged into one another? Yuck!
Moses gets more specific. He writes that man was created first and then given a job. Afterwards he sought to create a perfect companion and helper for the man and he created woman. This role of being man's "helper" may sound denegrating to our modern, unhelpful culture, but is actually a divine title as this word in Scripture is most frequently used for God. He is "man's helper". God brings her to the man and he sings a love song over her, names her and makes love with her.
Moses' history continues. He writes that in marriage these two creatures which are distinct in gender become "one flesh". Obviously this is directly about sex, BUT Christian commentators have always seen so much more in this than JUST sex. It is a unity of two things which are distinct. (This word "one" is later used to describe the distinct yet unified relationship of the Trinity, a relationship of equality yet difference Deut 6.4) Jesus quotes Moses here, "the two will become one flesh". Jesus says that in sex and in marriage as a whole, these two distinct creatures, one masculine and one feminine perfectly fit together like two differently shaped yet perfectly fitting parts of a puzzle.
As you know the opening chapters of Genesis do not end well. Adam sins with his wife and the two receive curses. Adam is held chiefly responsible (and thus his curse is exactly twice as long in the Hebrew). Eve is also held accountable for her sin. They do, however, receive different curses according to their differences in creation. Eve is cursed in the area of domestic relationships. Adam is cursed in the area of his work.
This is the story to which Jesus specifically referred and thus validated in his teaching. I believe it shows that gender uniquenesses are a wonderful, exciting thing which God put into the world at creation and which should be celebrated rather than the current trend which down plays or ignores them.