Translation:Your child will want to be a doctor.
Well, maybe it's a prophecy, maybe it's an opinion of your mother-in-law, or maybe you just talk about medicine so much and present it so well that it seems obvious that your child will want to follow in your footsteps and become a doctor as well. Or maybe that's just a sentence that teaches grammar of Future Compound.
Yeah, a Pole told me the same when I asked hi about the possible context, "opinion of someone else". I'm not sure I liked your last sentence though. Sentences that don't enable learners to understand WHEN they should use the future compound are clearly not a good way to teach the grammar of future compound.
Hi. I agree with Ashibaal. Knowing why and in what context a form is used is just as important as knowing about its structure. And using a sentence which doesn't make a lot of sense in English doesn't really help.
Outlandish sentences like "The blue turtle reads a newspaper while the birds watch television" (the Catalan course is full of them) are fine, as they just need a stretch of imagination.
But I'm afaid I find sentences like this faintly annoying, as I have to spend extra time figuring out what they're trying to say.
Having said that, the English on this course is generally more natural than that of some other Duo course I've seen.
I've checked the Polish National Corpus for the following syntax:
[pos=bedzie] [pos=inf] [pos=inf]
[Future form of być] [infinitive] [infinitive]
I've got 6 results, 3 of which were impersonal forms: Trzeba będzie / najlepiej będzie... where this actually sounds acceptable.
Now I've entered:
[Future form of być] [past-stem verb] [infinitive]
I've got over 1000 results.
So, such a construction does exist, but it's very rare and definitely stylistically unpleasant.