People have full reproductive control. That includes the ability to change sex at will, to control fertility, to pause pregnancies, even to get pregnant, change sex, and go through pregnancy as a man
Beyond what the other reply said, there are also examples of societies that have 3 genders - for example, the people of Azad in The Player of Games have male, female, and apex (I think they do have the tech to change gonads, but would not use them because their society is turbo-sexist. Also CW for all sorts of gender stuff in the Culture series, it's NOT all sunshines and rainbows for the people outside the Culture itself).
'I feel you want to take me,' Yay said, 'like a piece, like an area. To be had; to be possessed.' Suddenly she looked very puzzled. 'There's something very I don't know; primitive, perhaps, about you, Gurgeh. You've never changed sex, have you?' He shook his head. 'Or slept with a man?' Another shake. 'I thought so ,' Yay said. 'You're strange, Gurgeh.' She drained her glass.
actually the Gethenians are strongly beholden to a biological cycle of sexlessness and sexuality and if anything have less control of their sexual capacities and desires than more familiar humans
Which is possibly better because you won't have all these horn dogs posting horny on main and such. Everyone will be in normal mode until the orgy period starts for a few days then another month or so of normal.
Hey now, I'm with you but on the other side. I'd love to sprout some titties to clap for fun (but please make them go away to keep my back from hurting).