Why is almost every hybrid on the show half human?

I would think that by Trek's time, birth control is as simple as a one-time shot with a hypospray which is forever 100% effective until reversed with another such shot.

Although in the ST III novelization, it is implied that birth control is a simple matter of will (David and Saavik are talking about it and David says something about "I passed all my exams in bio-control").

 

A matter of will,

So if it's just reversible shot (and I think this is mentioned in DS9) then why was Kirk not up to date? One of the deals where the doctor has to nag the captain to get to sickbay I bet.

 

Well, according to some politicians, woman have ways of preventing pregnancy by sheer willpower even now! Especially if it was a legitimate rape!

 

On DS9, Kasidy Yates got pregnant primarily because bother her and Sisko forgot to take their birth control medication. If such a thing can happen in the 24th century, it can happen in the 23rd.

 

Nothing's ever 100% effective, except hysterectomies. Would the magical medicine of 24th century Trek really have a way to remove a uterus via hypo and return it with another hypo?

 

She'd become part of the crew, so she and James could carry on their relationship. Picard's Data to Kirk's Rayna, except that there's a love interest as well. Rayna would augment Spock as a scientist/researcher/etc. And then of course, you'd have to have an episode where Rayna sacrifices herself to save others and... that would be that. Kirk is single yet again.

 

Is there any reason -- any reason what-so-ever -- that this needed to be inserted into this discussion?

 

The first brings to mind Aeryn Sun from Farscape, the Sebacean women had the biological ability to not conceive and to "pause" (or reject) a pregnancy at it's earliest stages, and then months or years later deliberately continue the child's development at a more advantageous time.

The second sound like the Fremen in the novel Dune. Boys would taught in their teen years how have sex without ejaculating, an adult male who never learned the method would be unable to find a partner or wife, and to a minor degree be considered a danger to the group.