It's a children's TV show about a teacher who keeps getting stripped naked. Every episode includes some accident or prank that ends in nudity, or at the very least Machiko showing her underwear.
Yes, this is the same anime industry that gave children Cutey Honey and Fist of the North Star. Japan's PTA didn't like those either.
In many ways, it's harmless and even a bit charming. It really is a children's show. The artwork isn't sexy and the stories are kiddie runarounds. Machiko herself is a good-natured lady who laughs off everything and never gets angry. She doesn't actually like being naked in public, but it doesn't seem to faze her much and all she ever does is get embarrassed and say "maicchingu".
What's more, she's SuperTeacher. She can beat up crooks, do pretty much anything after only a minute's practice (e.g. skateboarding, voice dubbing) and solve her students' personal problems. She's an action heroine. In ep.24, she does Indiana Jones stunts on a rope bridge over a chasm to save a student.
The nudity I don't mind. It's quite funny and you've got to admire the way that the show's so relaxed about showing the human body. Nipples in the title sequence, full-frontal male nudity... it's all fair game and it's quite refreshing to see Machiko continually refuse to freak out about it all.
No, the problematic element is Kenta and his friends. They're three boys in Machiko's class who love groping, skirt-flipping and playing practical jokes. (Their victim isn't even exclusively Machiko, since they'll do the same to the girls in their class and to other female guest characters.) It's sexual harassment, albeit only from eight-year-olds, and they don't even think they're doing anything wrong. Worse still, the show shares their worldview. We're supposed to see their antics as harmless and normal. There's a girl in their class who'll get grumpy if she's the only one not being molested, for instance. (She's fat and she has a soft spot for Kenta.) Those pre-pubescent sex offenders are practically the heroes.
Admittedly the show likes turning the tables, stripping and embarrassing the boys when one of their pranks backfires. However to call this fair exchange would be to accept the implied premise that unwilling male nudity is the same as unwilling female nudity.
Machiko never gets angry at those boys, but I think she should have. She's supporting their belief that their behaviour's okay. Who's to say that they won't still be doing this in ten years' time? (At least one of Machiko's colleagues is just as keen on seeing her naked, for instance, although admittedly he also wants to marry her.) It's hard to get too indignant at this gentle exercise in kiddie fluff, but it's fundamentally a children's show with the messages of "sexual harassment is normal" and "it's funny to treat women as sex objects and humiliate them".
Children in the audience were copying this, incidentally. There's a good case for calling it more unsuitable than, say, Fist of the North Star (another 1980s anime that was notoriously shown to children). Children will always copy what they see, but no one can do what's in Fist of the North Star. The nearest you can get is shouting "abeshi" or "hidebu" as you pretend to die in agony as your skull explodes.
If you can live with all that, though, the show's quite fun. Machiko herself is great, the show is kind-hearted and all that nudity is surprisingly entertaining. It's not remotely sexual, but it adds some naughtiness and that's always a boost in a children's show. Every so often they'll also have dream sequences. These have aliens, flying saucers, time machines, etc.
Also, in fairness, the show's capable of criticising gender roles. Ep.73 has one of the boys getting teased by his friends for sewing.
This show has lots of live-action adaptations. Wikipedia know of eight in 2003-2009. Bearing in mind the Kekko Kamen live-action films, I'd suggest extreme caution.
This is a very odd show. It's fairly notorious in Japan and a pioneer in ecchi anime, despite being really tame. (Lots and lots of nipples, though, even in the title sequence!) Despite its eyebrow-raising concept, this really is for children. It's lightweight and almost entirely dispensible, despite the odd episode that manages to tell a slightly more meaningful story, and I usually had it on in the background while doing something else. I disapprove strongly of what it's saying, yet Machiko herself makes the actual episodes charming and likeable.