It's every mother's greatest fear that she will have to leave her children. My daughter Kate Gross lived with that fear for more than two years, before she died of colon cancer a few weeks ago. I wish she was here now so I could tell her that the boys are getting on just fine. Oscar and Isaac were three when Kate was first diagnosed. Twins, but very different little beings. Oscar dark-haired, violet-eyed, solid - and with an astonishing ability (in Kate's words) to 'focus on things, to know them utterly'. Isaac, blond and agile and restless. 'Each of them,' she says, 'carved out his own space in my heart, a space which fits him exactly.'