Everyone Wants a Gas Stove, but...
This article from WP suggests gas stoves are causing asthma, maybe up to 650,000 cases so far. Combustion products from gas stoves include CO, CO2 and NO2.
According to the article, stoves leak methane, CH4, even when not in use. Of course, a good draft hood vented to the outside helps, but many homes don't have these.
And I see older, small condos with full size new stoves in them, which designers hadn't planned for.
Personally, I really like electric ceramic cooktops. They heat quickly and are much easier to clean.