Year round hot weather. Hyper-sexualised advertising campaigns. Brothels and glorytoriums on every corner. A perpetual labour shortage. Children taken away to corporate boarding schools. The loss and sequestration of Old World inhibitions and neuroses. Four hundred years of advancements in the fields of genetic engineering and cosmetic surgery, and the eradication of transmittable diseases.
Sex is the inevitable consequence of all these ingredients. Not to mention, it's probably the cheapest and most fulfilling way for two or more people to spend their time, when the whole world has been commodified. Corporations heartily encourage it, as children born in their territory are de facto employees of that corporation, and increase market share through sheer weight of numbers. Marketing campaigns are awash with attractive bumps and bulges dedicated to catching the eye.
With genetic engineering and embryonic manipulation being so affordable, designer babies become attractive people, and its only deluxe packages like Elf ears and longevity that cost significant amounts of money. For adults looking to augment their sexual experience, walk-in, walk-out stem-vat clinics allow for increased lubrication, lactation or sperm production, as well as increased or altered sizes, shapes and girths of sex organs. As a result, partners pair off after quick discussions about sexual compatibility, matching fetishes and aligned schedules. Polyamorous relationships are frequent, both as an accepted and embraced part of modern culture and a way to slash and share bills for living in megacities.
For those looking for a more premium experience, corporate-backed brothels are built and financed alongside franchise storefronts, allowing for waitstaff to serve customers in multiple ways. For example, stores like Futas and Footlongs serve hot dogs, with the option to "warm up a customer's mouth" before or after their meal. For those looking to earn some creds on the side, Glorytoriums are prevalent throughout megacity levels, allowing anyone to rent a hole in the wall for a few hours and keep any earnings they make. Glorytoriums allow for the thrill of quick release while maintaining anonymity.
While lots of people feel they're born in the correct body, many people experiment with their exterior visage and genital configurations to find their perfect selves. The process of switching from one sex to another takes a few hours in the stem-vat clinics, but there are those like Jesse the Gunslinger that have augmented their pelvis to allow for day-to-day switching of fully functional organs. It's rare to find someone that hasn't at least dabbled in becoming the opposite sex, and those that haven't are either extremely poor, extremely busy, or are too far away from any cosmetic hub to bother with the experiment. Many people maintain a vague or androgynous build specifically so that they can embrace a non-binary life without the need for constant spending for reconfiguration at the clinics.
The spectrum of gender has been fully embraced in the New World, by civilians, adventurers and corporations alike. For corporations, the explosion of fitted fashion has opened up new marketing demographics; summer dresses and skirts for masculine and androgynous frames are billion cred businesses, genderfluid actors can fill any role available, and jobs that require strength and stamina often provide them to anyone willing to sign the contract.
Among the citizenry, transformative events are little more than a fun surprise to those close to the newly gendered, though such events do provide a fun and light cause for partying, especially when megacity denizens often have little else to celebrate. Any sudden sexual incompatibilities between partners and polyamorous relationships are addressed and either worked around, or partners separate amicably.
For adventurers, guns, melee weapons and techs are the great equalisers of combat. Height and muscle mass do little outside of unarmed wrestling, and as such, adventuring parties are always willing to accept a person regardless of gender or sexual identity.