There are genetic engineers that have been able to make tear free onions. Chopping onions make people cry because an onion releases an enzyme that makes a gas that contains sulfur, which irritates the eyes. Scientists have found out how to turn off the gene that makes the enzyme to come up with onions that are the same in every way without causing stinging or teary eyes. They won’t be sold in grocery stores for at least another 10 years because it would take a while to mass-engineer them.