Her studies, which focus on the challenges facing human reproduction, conclude that humanity is facing an "existential crisis" in fertility rates as a result of phthalates – a chemical used when manufacturing plastics.
She discovered that male (human) babies who had been exposed to the phthalates in the womb had a shorter anogenital distance, which correlates with penile volume.
The chemical is used industrially for making plastics more flexible, but Dr Swan warns that the chemical is being widely transmitted into toys and foods.
Phathalates mimic the hormone oestrogen and so disrupt the natural production of hormones in the human body. Researchers have linked this to interference in sexual development and behaviours.
Reducing the use of this polluting chemical is necessary to protect the future of the human race, Dr Swan argues in the book.
She believes that rapidly decreasing fertility rates – measured in a series of studies – means that most men will be unable to produce viable sperm by 2045.
So, who will be joining Greta at the next climate strikes?