This is a fairly good starting point, but if she's worried about unknown and unproven effects then there's nothing I can really do to help, other than to point out the statistics just don't support the presence of such an effect. The few (usually flawed) studies that have shown a cancer correlation also point out that the risk is still one in several tens of millions, and there comes a point at which a potential risk becomes so unlikely that it just isn't a risk anymore. Some studies have even found a negative correlation, i.e. found that people living closer to masts are less likely to get cancer.

You'd be better off spending your time and money worrying about risk factors which can provably affect your baby's health, such as diet and nutrition. A well-fed child with a 3KW cellphone mast in their bedroom will live MUCH longer than a child fed on junkfood hundreds of miles away from any mast.