I have two children, age 14 and 5. Eldest was recently diagnosed with ASD and is in the waiting list for ADHD (but we've been told he almost certainly does have it).
When my son was young it was said autism was not genetic. We also didn't realise for a long time because he just seemed like a "wild" boy, he was our only and we had no comparator, and primary school fobbed us off when we expressed concerns about his behaviour. (To be fair he is high functioning, does not have sensory issues and the ADHD element is the bigger problem = complete lack of focus.)
We had secondary infertility so a big gap between the two, so statistically there should have been a higher chance of a second child having ASD but we didn't really start to realise that was the issue with eldest until year 6 (by which time our second had recently been born).
During his assessment process it was noted that I also have many of the female-presented ASD traits (I was relieved actually, is spent my life feeling like a square peg in a round hole, desperately trying to fit!). I also realised my dad probably has aspergers (it would explain so much) and my sister and her eldest son also show many traits.
Had we realised earlier, we may well have decided not to have a second child, but thankfully she seems completely NT.
I love my son to bits and understand him very well now. But he will always have his struggles, especially with social life/friendships, which is so very sad at times and I worry about him a lot. I do sometimes think it might have been better not to pass on my ASD genes, yes.