I recognize that it used to be difficult to find a book where the main characters would even spare a sentence in the direction of birth control and sexually transmitted infections and that we have made serious improvement. It still irks me when the characters step over the STI portion and focus solely on the contraceptive aspect, but it's something. And I recognize in real life people have trouble with these discussions to (myself included). And certainly people should not be looking to books for role models in this respect. But, my god, it's almost worse to watch/read two characters have a half-assed discussion than for them to have no discussion at all.
In a recent scenario I came across, the two characters are well on their way to getting it on when the hero remembers he needs to go get a condom. The heroine tells him he doesn't need to. He stops to clarify - she responds he told her he got all his shots and they don't need birth control and so they continue on sans protection. Now first, I'm going to assume that "having all your shots" is being used in some sort of euphemistic way because it is a stupid, dated, and inaccurate phrase for two people in their thirties to be using, in my opinion. (The book was printed 2003.)There is no mention of her health status. And of course the two never follow up on the conversation to clarify what she meant about birth control being unnecessary. Because it could mean many things.
-It could mean she doesn't mind getting pregnant.
-It could mean she thinks this is a "safe" time in her cycle.
-It could mean she has a moral objection to birth control.
-It could mean she is infertile.
-And it could mean she is on some sort of birth control already.
Now of course the hero assumes she is on birth control and the heroine meant to say she had been told she was infertile since she had previously been unable to conceive. But of course it turns out she is not infertile. Now fortunately they fall madly in love and both apparently want children so this is a happy surprise, but since neither of them discussed their feelings about children that is due more to luck than anything else. And oh my god that irks the hell out of me. (In case you couldn't tell.) Because they could have just used a condom. It wouldn't have hurt the story, it just would have saved the surprise pregnancy. Or they could have completed the conversation. Or the condom could have failed, leading to a follow up (which I have seen done beautifully). There was no reason for the characters to make such assumptions except for contrivance.