Note: I'll write only about the books I've read, other folks might have other points of view.
Heinlein might have had a weird way of looking at things but he has great stories as an introduction to the scifi genre - light(ish) reading with plenty of topics to discuss.
Take two of his works that I recommend to folks, Starship Troopers and Farmer in the Sky. Both are "juvenile" books - sex and misogyny are themes in Heinlein's later works - but deal with life in space in a very realistic way. They're wildly speculative yet, just barely, they're plausible enough to make sense.
If you're looking for short stories, there's The Man Who Sold The Moon - short stories populated with really far-fetched ideas yet it's a really fun read.
I'm sure other people will suggest other things but I strongly suggest you take a look at Heinlein for the kids, after all he wrote a bunch of stories for them that are easy reads and are, as far as I can remember, kid-safe.
I'm resisting recommending more authors - as I'm sure this thread will be full of them - but Heinlein's earlier works, from what I recall, are nice examples of scifi aimed towards younger audiences.