From the article:
Human tissues exposed to either drug for one week in a dish had reduced numbers of cells that give rise to sperm and eggs, called germ cells, the study found.
Ovaries exposed to paracetamol for one week had more than 40 per cent fewer egg-producing cells. After ibuprofen exposure, the number of cells was almost halved.
Experts say this is important because girls produce all of their eggs in the womb, so if they are born with a reduced number it could lead to an early menopause.
Painkiller exposure during development could have effects on unborn boys too, the study found. Testicular tissue exposed to painkillers in a culture dish had around a quarter fewer sperm-producing cells after exposure to paracetamol or ibuprofen.