HARD-nosed Newsnight presenter Jeremy Paxman was recently reduced to tears when he discovered the appalling circumstances in which his ancestors lived and died.

Family history sparks all sorts of emotions in even the most cynical of people, according to Dan Waddell, author of the second book in the Who Do You Think You Are? series, accompanying the new BBC Two series, in which Paxman appears.

While some believe genealogy to be duller than ditchwater, Waddell says it can change some people's lives.

"It's not just about tracing your family back to William the Conqueror and developing this very ornate family tree," he said.

"There's this image that family history is followed by people who are at a late stage in life.

"One of the things that attracts people of a different generation is this idea that you're going to find out a family secret. Finding out flaws and secrets brings these people to life.

"There are some people who say knowing about your ancestors makes absolutely no difference to your life

"I don't subscribe to the theory that we are defined by who our ancestors were. We are more than an amalgam of genes passed down to us.

"However, it makes you more humble to know you come from a long line of people who struggled and lived to overcome some very difficult circumstances. It doesn't influence who you are but it definitely influences where you are and how you came to be there.

"You can see who were the movers and shakers in your family and the people who altered their path. In 1850, perhaps your family were living in abject poverty in a slum in a provincial town and yet you might be in a different part of the country in a different economic class. How did that happen?

"Death certificates are fabulous sources of information because they tell you how somebody died and that can quite often tell you about how they lived.

"If someone had died of tuberculosis in their 30s or died during a flu epidemic, you get a sense of how they lived. It brings them to life.

"It's very compulsive and can take over your life."

In his latest book, he gives tips on everything from getting started, to how to discover secrets and explode myths in your family tree.

Apart from the tearful Paxman, other celebrities who research their ancestry in the new series include Julian Clary, Jane Horrocks, Stephen Fry and Sheila Hancock, whose histories produced some surprising results.

Waddell traced his own family tree for research purposes and immediately discovered a family secret - that his Catholic grandmother was five months pregnant on her wedding day.

"The problem is, when people discover something like this, how do they present it to their relatives?" he said.

l Who Do You Think You Are? Discovering The Heroes And Villains In Your Family, by Dan Waddell and Nick Barratt, published by HarperCollins, priced £14.99.