Well sure it's possible for certain chemicals to mimic hormones in animals, which might cause issues similar to what they're talking about in this story. And, most of us here can testify to what hormones can do to us, mentally and physically.
But the jury is out on if it applies to us being trans or not. Maybe it's genetic, maybe it's chemical, maybe mum drank some dirty tap water when she was pregnant, maybe robots from the planet Transatron1138 have been irradiating us, maybe there's no reason at all... there doesn't always have to be one.
We're here, and we are... regardless. I say we make the best of it :-)