Broody, but overweight? In some parts of the country, you won't get fertility treatment until you slim down - but try somewhere else, and you might be all right.

Over 40? Sorry, you're too old for help. But lesbian? Single? Welcome aboard.

Can there be any excuse for such apparently perverse decisions? Well, you might be surprised. Because doctors say that if you're obese, it's harder for you to get pregnant; and if you get complications at childbirth, surgical intervention could be risky.

Over the age of 40, women are far more likely to have babies with medical conditions like Down's Syndrome than their younger sisters, whether lesbian or straight. Younger women are also far more likely to fall pregnant through IVF in the first place.

And, it's argued, gay couples and single women can provide just as loving a home as a heterosexual man and woman.

These arguments enrage thousands across our country. Some wonder what has happened to the role of the father; others, with painful health conditions, have been told they must wait for their operations, and fail to see why healthy people should get NHS resources before them.

Then, others describe how their aching need for children haunts them every day of their lives.

Who would choose between the patients, in this world of ever-increasing medical possibilities and ever-tighter purse-strings?

Doctors and health managers have to make these heartbreaking decisions every day. They will have to do so until, as a mature society, we decide we are either willing to pay for a service that meets all needs, or ready to accept that not everything that's possible should be paid for from the public purse.