Is using Teflon cookware safe please answer YES or NO and explain it.?

It's safe if you follow a few rules:

Do not to put an empty teflon pan on the burner. The teflon coating can emit fumes that can cause flu-like symptoms in humans, and can even kill small birds. Always put a little oil or butter into the pan to preheat. So if the recipe calls for searing something on high heat, use an aluminum or cast iron pan instead, not teflon.

Never use a teflon pan in the oven.

If you're that worried, switch to anodized aluminum. These are aluminum pans that have had a special treatment to make them non-stick like teflon but without using teflon. Anodized aluminum is very tough and can even handle metal utensils (unlike teflon.) Be sure to read the manufacturer's directions carefully though, or you can end up damaging the anodized surface. Handwash your pots and pans - never put them in the dishwasher. Also, avoid having the pans bang or scrape against each other as this will damage the nonstick surface.

at low temperatures it is safe, if heated to the extreme it is cancerous