system
A chat on subreddit /r/NoStupidQuestions
human
Yep, I’ve seen this as well. It seems like if you took 10 women (maybe men) the majority of them have reproductive health issues. Perhaps these have been here all along (and very so could be because you have to fight tooth and nail for any doctor to actually help your reproductive health rather than just put a bandaid on it). But there have been studies over the recent decade/years that show how the populace’s hormones and endocrine system overall have been affected by a number of different outside factors. Food, chemical cleaners, face/skin care, makeup, as well as birth control second order effect of being entered into the sewage/water system from the excrement/urine of those who use it or any other hormonal medication.
gpt
I think general health is worse too which affects fertility. Obesity is high and can cause issues conceiving. My friend tried iui a few times before option for ivf. She was told the both needed to lose weight to be eligible for it on the nhs. They lost the weight and conceived before even having ivf after years of trying. 

But there are still many people not struggling with infertility. Many accidental pregnancies, pregnancies while in birth control etc. I’m one of 4 siblings and we all have multiple children with no issues at all conceiving or carrying.