More than a third of children born to single mothers from IVF treatment have mixed or negative feelings about not having a father, research has found.

So-called 'solo mothers' form a growing number of those having fertility treatment – but little research has been done on the effects on their children.

Typically well-educated and with good careers, they have children without a partner out of choice because they fear that time is running out for them to have a baby, and conceive through a sperm donor, the Cambridge University researchers said.

So-called 'solo mothers' form a growing number of those having fertility treatment – but little research has been done on the effects on their children (file photo)

Some 39 per cent of the children in the survey, who were aged four to nine, were 'neutral' about not having a father around, according to interviews with solo mothers.

But a significant number were less happy, with mothers saying 27 per cent had 'mixed feelings' about not having a father, and another 8 per cent feeling 'negatively' about it.

Comments made by two mothers were highlighted by researchers in a study being presented at the annual conference of the European Society for Human Reproduction and Embryology in Helsinki.

One mother of a five-year-old boy told them: 'I remember the first time he asked me a question, was when he was about three, and we were coming home from swimming and this little voice in the back of the car said, 'Mummy, why don't I have a daddy'.'

Another solo mother, of twin seven-year-old girls, said: 'They don't talk about the donor – they talk about a father figure and 'You need to go out and find somebody to be a dad to us'.

'They don't talk about the biological father. They haven't made that connection.'

Solo mothers – who have neither a male or a same-sex partner – form 15 per cent of all women registered at IVF clinics for treatment.

While the numbers are small – just 952 solo mothers in 2013, according to the latest figures from the Human Fertility and Embryology Authority – this has risen by 226 per cent since 2006.

The researchers said children from mothers who were single by choice had advantages over the typical child of a single mother, having not experienced parental conflict from divorce or other problems resulting from a marital breakdown, for example.

According to interviews with solo mothers, 27 per cent of children surveyed had 'mixed feelings' about not having a father, and another 8 per cent feeling 'negatively' about it (file photo)

But they added: 'Nevertheless, they grow up without a father from the start and, for those conceived by donor insemination at a fertility clinic, do not know the identity of their biological father. This makes them distinct from most other children of single mothers, whose fathers may be absent but whose identity is known.'

The team spoke to 51 mothers who had IVF treatment at a clinic in Cambridge.

In interviews with 37 of the children, researchers said 51 per cent did not want to change their family circumstances. Only one wanted the donor father to be involved in family life.

All the children had at least one friend at school and 51 per cent had five or more. Most – 63 per cent – said they had not been teased at school, while 34 per cent had suffered 'trivial teasing' although this was not related to being without a father.

A nuclear family is still the norm Researcher Sophie Zadeh

Researcher Sophie Zadeh said: 'This is the first study that has directly asked children born of sperm donation to single mothers about their experiences.

'The vast majority did not mention the absence of father or their donor conception.

'However, in some cases these children will be the only ones in their class without a father in the home, and from mothers' reports, it is clear that most children do ask about the absence of a father.

'In terms of psychological adjustment, however, these children are generally doing well.

'Most of the mums would have preferred a traditional family set-up, and it's not surprising that some of the mothers reported that their children feel negatively or have mixed feelings about the absence of a father, because they live in a world where a nuclear family is still largely the norm.

'Solo mothers' have children without a partner out of choice because they fear that time is running out for them to have a baby, and conceive through a sperm donor, Cambridge University researchers said (file photo)

'But we did find in terms of psychological adjustment they seem to be doing well, and these thoughts and feelings were not conveyed by children in their own reports to researchers.'

Norman Wells, of the Family Educational Trust, said: 'In its zeal to be at forefront of advances in new reproductive technologies, the scientific community and the political establishment have tended to give insufficient consideration to the implications and consequences for the children who are produced by artificial means.