Surprised no one has pointed out that eating foods high in B complex like brewer's yeast, or taking B complex vitamins, also makes yellow pee. I can testify to this! So rather than being toxic, it's exceptionally healthy!
Re the fetus being bathed in urine as Water Of Life explained--it's occurred to me that if we undertook, for nine months, an intensive program of intermittent fasting on urine, along with massaging it into the skin and a nutritious and light diet, this would be highly rejuvenative,
At the end of the nine months we would be "reborn"!