Sperm is big business. For years sperm banks have been seen as a viable route for those wanting children but, for one reason or another, have been unable to conceive naturally.

For many that have been conceived via a donation, there’s a feeling in the back of their mind that wonders what this missing biological figure is like. Before the advent of the internet, wondering is pretty much all they could do, but with the super information highway in reach of everyone’s fingers, information is far more accessible.

JoEllen was one such quizzical child. Although she was happy enough being brought up by her mother, she was always curious as to the other side of her family tree. Was she anything like her biological father? And did she have any half siblings? One website could find out.

The Donor Sibling Registry allows fellow donor children to locate others who were born from the same sperm donor. This allowed JoEllen to track down a half-sister in New York. The New York Post was so interested in their story that they run a piece on them. It told their story, including how they came about thanks to the hands-on contributions of donor 150.

Sitting in his broken down RV in a car park in Venice Beach, California, is Jeffrey: a self-confessed beach bum, animal lover/owner and free spirit. Oh and AKA donor 150. Touched by this story, he gets in touch with JoEllen and agrees to meet with her and the other siblings and the result is quite possibly one of the oddest family re-unions ever.

Listen Jeffrey, I thought we decided that it was my turn to drive. You're waaay too wasted; you thought that traffic light was talking to you!

Jerry Rothwell’s documentary is a fascinating account of fractured family members looking for answers. All of the siblings featured, and there are quite a few of them, seem to believe that the absence of a biological father in their lives means that a part of their own life is missing. This is something they all appear to want to rectify.

It’s only human nature to want to discover one’s roots, but it obviously becomes trickier when your biological father has the right to his anonymity, hence the numeric title 150.

Although JoEllen’s particular journey has a relatively happy ending, it’s easy to imagine that many do not. After all, presumably if donors wanted children of their own, they wouldn’t sell them in a jar to sperm banks without giving their names.

There’s also an element of the absurd about her search; she appears comforted to not only learn of others that share half of her genetic make-up, but to meet up with them. If she was to carry out her search until it reached its limits, she could be searching a long time; Jeffrey had been donating his sperm up to a couple a times of week for eight years, as the donations paid for his rent. That could lead to one hell of an extended family. At what point will JoEllen will say enough is enough? Half-sibling 245? 1,987?

Although the documentaries ending is one of quiet resolution for JoEllen and her half-siblings, there’s also the overall feeling that you should be very careful for what you wish for in life, because there’s nothing to stop the truth from being a bit of a disappointment.

For anyone in a similar predicament, it may well make them think twice about tracking down their own sperm donor of a dad; sometimes we should just learn to appreciate a welcome gift, without having to track down who gave it.