In last Monday's inaugural episode of the BBC's make me a trader programme, conceived undoubtedly in the olden days when trading was a glamourous career rather than one whose practitioners live in daily fear for their survival, two things were amply clear: the woman and the older man were rubbish.
Out of eight would-be traders, only two were female and one of them sobbed for a full 90 minutes and was too neurotic to place a trade.
Meanwhile, the oldest wannabe - a 63 year old ex-IBM man - placed a buy order when he meant to sell and then bought into Bradford & Bingley on the cusp of its demise.
In one 60 minute programme, the BBC therefore illustrated a) why one London trading floor apparently has three women and two hundred men and b) why most traders retire before they're 40.
The notion that young men do it best is backed up by research from Cambridge University showing links between testosterone and success in high frequency trading. With the possible exception of bearded women and Rupert Murdoch, testosterone is highest in 20-something males.
"Testosterone peaks at the age of 21 and drops over the course of your life. In your 40s it literally falls off a cliff," says John Coates, the former Deutsche Bank trader leading the research.
Coates' widely publicized research shows successful traders have often been exposed to high levels of testosterone in the womb.
Exposure can be measured by comparing the lengths of the index and ring fingers on your right hand: if they're roughly similar, you were born to be a day trader. "It's hard to measure by sight - you're best off photocopying your right hand and using a ruler," Coates advises.
A more conspicuous indicator of current testosterone levels may well be acne. In the BBC's programme, the 30-something man and "successful [hedge] fund manager" managing the novice team had a large boil on his cheek.
Masculine names may also be relevant - the 'top City trader' and former Goldman director stumping up the cash for the novices to work with is called 'Lex Van Dam.' Laura Smith doesn't sound quite the same.