How I remember when my son James was about a week old (I was a second year medical student), and I came home to the first night in the house on own. The first week, we had stayed with my mum, and parenting seemed so easy. I took off his nappy and thought he had some terrible disease all over his bottom. I rang my GP, and asked her to come over straight away. This was an emergency. After I explained the problem, she refused to come, and told me off. It was nappy rash. I felt really stupid, but I really hadn't known what to do. It's amazing that we're not allowed on the road without a driving test, we can't drink alcohol until we're 18, yet we can enter into parenthood without any qualification.

I became pregnant at 21, and was faced with a screaming nappy-wetting thing, that I loved enormously, but who seemed to wake up just when I needed the toilet, or if I stepped into the shower. I learned that this was the pattern for the next million years. 15 years later I'm still not allowed in the bathroom for more than five seconds before alarm bells ring and the troops invade. If we'd known what it was like to be parents, we would have all been sterilised after our first period

After an awful night with James, I looked up "sleep" in my "expert" book. It talked about getting the baby to sleep, but nothing about me. I was the desperate one. My little cherub dropped off when ever he felt like it.

Are we prepared for this great event? Yes. We go to antenatal classes and learn how to puff and blow for labour. Then we are warned to do our pelvic floor exercises. They forget to say you don't need them for another 25 years, because you are either too knackered, or your kids have an early warning system that activates if you come within five yards of your partner. Perfect contraception.

I've seen successful professional mums, used to making huge financial decisions, turn to blubbering wrecks on becoming mothers. Which cream for the tail end? Which milk for the top end? They are intelligent women but they are at a loss to know what is right or wrong. Could training have helped? Certainly.

Something happened the other day which made me sure we need some sort of parenting classes.

I was working in an "out of hours" centre. At 9.30 on a cold night, three forlorn characters came in. The youngest, six-year old-Rose, was in pyjamas and clutching a toy bunny, and had been discharged from hospital late that afternoon. She had been in for several days because of asthma. She was now very short of breath. Next came her sister Anna, who was eight years old. Lastly, Jane came in. She was a young girl of 16, looking exhausted, and who turned out to be the baby-sitter.

She herself had had a baby a week ago. I tried not to look too surprised. Jane said that Rose's Mum had gone out for the night, and she didn't know where or when she would be back. There was no father around.

I asked Jane what medication Anna was taking. Jane looked blankly. Anna, the eight-year-old, who seemed too street-wise, told me when Rose last had her inhalers. I was really concerned for Rose and Anna's welfare. What mother would leave her child with a young baby-sitter for the night, after the child had just come out of hospital?

Books don't offer all the answers. Why should anyone know exactly what to do? Often, we don't have parents and older sisters close by to provide support. If parents are referred to social services because of lack of care, what do we do? We take their children away from them.

We need to offer more than antenatal classes in the first few months of parenting. Training and support are vital all the way through. The goalposts move all the time in parenting, and we practise on our kids to get it right.