Human Chorionic Gonadotropin (hCG) is a glycoprotein hormone produced during pregnancy that is made by the developing embryo after conception and later by the syncytiotrophoblast (part of the placenta).
Levels of hCG in the blood or urine are a sure way of detecting pregnacy. But also suppliments of hCG have been used to assist in fertility and as weight loss solution. To reduce the sensation of hunger so you eat less but still feel full. This is often lead to a lot of malnurished dieters and has been banned in the US and Canada as a acceptable diet product.
But then Balls has never been much for following the rules.
And thus solving the mystery of who is the father.