You need not have any anxiety about your son's health.
->
You needn't be anxious about your son's health.

At least in US English, "You need not have any anxiety about your son's health" is okay.

Thanks, @AlanF_US. I wasn't so much suggesting that the sentence wasn't OK, more suggesting how I would word it instead.

I see.

There are a lot of orphaned English sentence which, while not wrong, are, to my ears, awkwardly or in some way problematically phrased. Before adopting them, I'd want to edit them. I started out leaving a comment on some of them with an alternative wording, and tagging them @change. This was an attempt to get some consensus for a change, instead of of just grabbing sentences which might sound fine to others (such as the current sentence) and changing them. There's also the issue, of course, of whether the existing translations would still match the edited sentence.

I know that plenty of people have addressed this topic before. I wonder if we can get over this inertia, though, and do something to reduce the thousands of orphaned English sentences.

Could you suggest a better tag to use whereby attention can be brought to such sentences and some sort of consensus about what to do with them can be reached?

My own view is that orphaned sentences are fair game for adopting and modifying at will. I base that view on my own reading of the guidelines, as well as various things that Trang has said over the years. If you modify orphaned sentences that are awkward but correct, you may run into some opposition from people who interpret the guidelines differently, but you can deal with that as you see fit. However, you wouldn't get opposition from me for modifying any orphaned sentence, even the rare ones, like this one, that you might want to change but I felt were already correct and natural (at least to a US eye). Unless, of course, the change broke too many translations to fix.

On the other hand, achieving even partial consensus on even a single sentence is a lengthy and laborious process. I feel that extending it to thousands of sentences is just not feasible. Achieving consensus on a tag, and awareness that the tag exists, are by far the least of the problems.

I think the best thing you can do if you encounter an awkward sentence is to add a good one of your one. If you know the languages of sentences already linked to the awkward one, you can link them to your new one. You could even unlink the awkward one, and add an "unnatural" tag if you want. Remember that orphaned sentences are filtered out by default, so casual users don't see them.

I realize it's not very satisfying to have awkward-but-correct sentences sitting in our corpus, but given what I've seen in my ten years at Tatoeba (including various initiatives to "drain the swamp"), as well as the sheer number of orphaned sentences, I don't think there's a feasible path toward getting rid of a significant number of them.

P.S. Sentences from the Tanaka Corpus (like this one) are a special case, since the custodians of that corpus have particular goals of their own (such as coverage of vocabulary). Personally, I would be even less likely to focus on addressing them as a group.

Thanks for sharing your experience and the judgements you make from it, @AlanF_US. I'll take it into consideration as I deal with orphaned sentences.

Thanks.