Ah, I attended a meeting about this last year before Covid. I assume it is the same curriculum, it just got delayed? From what I can recall, though it was a while ago now:
The primary curriculum was shown to us and discussed. I attended as I was as concerned as you, OP. But it was very straightforward and uncontroversial. The furthest it went towards controversial was mentioning pretty briefly that all mammals, including humans, reproduce via egg and sperm (teacher specifically said that males make sperm and females make eggs, as per Department for Education slideshow/handouts explaining what is covered, which was a relief for me!)). That is covered when they learn about
how plants and animals reproduce in science lessons. It isn't covered until Y5/6, as is informing about periods, hygiene and so on (unless needed, she did say colleagues have covered it earlier with some children if their periods started, occasionally as soon as Y3).
They also cover that families are all different, some have gay or lesbian parents, some have single parents etc and we should respect that people may be different to us. That's covered as part of the general school values, anti bullying lessons and as and when it comes up.
And that was about it! I was all geared up for a massive debate and instead felt very reassured. I couldn't see what anyone would have cause to complain about, though I understand some may object to same sex relationships/sexual reproduction/periods being covered at all, however briefly, for religious reasons. The teacher stressed it was not possible to withdraw children from this curriculum as it would be with RE.
I've no idea what is happening in secondary schools though, as I've been informed of nothing by DS1's secondary school! All I am aware of is the ridiculous, nonsensical Youtube videos 'explaining'
LGBTQI...whatever the other letters are that DS had to watch during a Y10 'Values' lesson. I counted around 30 errors or contradictions in a 3 1/2 min long video and am compiling a very long email explaining what a crap resource it was, along with a link to better, approved resources that don't contravene the law!