Specifically, about helping other people have fulfilling sex lives, and fulfilling relationships to go along.
I spoke with Westheimer — better known simply as Dr Ruth — by phone in January. In her thick German accent, she told me about the issues she's been seeing since she first launched the public-radio programme "Sexually Speaking" in 1981.
I learned more about Westheimer's career, and about her philosophy on sex and relationships, from reading some of her books, including "The Doctor Is In" and "Stay or Go," both co-written with Pierre A Lehu.
Here are three of the most common issues Westheimer sees:
"People having expectations that cannot be met" is still a big problem, Westheimer said. In many cases, these standards were set by the media.
"Hollywood and the movies tell us that the stars have to be twinkling every night," Westheimer said. "That's not reality of life."
Some people are frustrated that they aren't achieving multiple orgasms or having "an erection like you see in sexually explicit movies," Westheimer added, though she sees slightly less of this today than she did 40 years ago.
"People have to be realistic and people have to be sexually literate."
Westheimer told me she still sees men complaining about premature ejaculation, and women complaining about difficulties reaching orgasm.
In "The Doctor Is In," Westheimer writes that she suspects these complaints keep coming up for two reasons.
One, "young people who begin having sex start out relatively clueless, and so there is a steady influx of new people looking for this information."
Two, "as long as someone's sex life seems to be working OK, they don't bother learning the finer points. But as soon as they run into a problem, since they're embarrassed to ask anyone else, they'll turn to someone like me."
Westheimer has said before that premature ejaculation and difficulties achieving orgasm are typically psychological, as opposed to physical, and that a sex therapist can help with both.
The tedium of everyday life, according to Westheimer, is the greatest danger to a romantic relationship.
In "The Doctor Is In," Westheimer writes that "sexual boredom is only a minor aspect to a couple's not having a satisfying sex life. Intellectual boredom with each other is a much bigger culprit."
She adds: "The first step to fighting boredom is to recognise it. One clue is that you're always tired even though there's no particular cause."
One potential solution? Instead of looking for ways to spice up the relationship itself, look for ways to add variety to your own life.
If that doesn't help, Westheimer says, you should seek professional guidance. Ultimately, you may opt to end the relationship — which isn't something to be ashamed about.