There’s no control. This is the same problem with the Darby research on finding parabens in breast cancer tissue. That they found parabens is not surprising since it’s a food preservative & urine is where the body gets rid of waste.
This study does nothing to answer the implied question “Are parabens causing infertility?”
Although I suppose the data does support the conclusion that the most commonly used paraben, Methylparaben, is not causing infertility.
It also hasn’t been replicated.