Men are less suited to be parents than women.
That, at least, appears to be the assumption that defines the way unmarried dads are treated in law compared to mums. Women's value as parents is usually taken for granted, whereas men must prove themselves. The system is supposed to work in the best interests of the child, yet in some cases it is letting children down by failing to support strong relationships between them and their fathers.
The problem is that some men who want to be good, involved dads are having to undertake costly, emotionally stressful court battles in order to win basic parental rights, when the vast majority of mothers gain those rights automatically.
Unsurprisingly, some men are being put off the fight and their children are growing up without the benefit of a close relationship with them, while in other cases, the court process is turning a bad relationship between the two parents into a nightmare, far from an ideal scenario for the child.
Unmarried dad Ron Park has submitted a petition to the Scottish Parliament calling for the law to be changed. Mr Park has a baby son whom he does not see because the child's mother does not allow it. "There is no protection issue, no order to remove me, she simply felt like she wanted rid of me," writes Mr Park on his blog.
Unmarried dads gain parental rights and responsibilities only if their name is on the birth certificate, but if the mother has registered the birth without the father, they can only gain recognition as parents by going to court.
This has been the case since the law was changed in 2006 and is an improvement on the previous position, under which unmarried dads had no rights at all to speak of, but it doesn't go far enough.
The law is out of kilter with the times. From next April, couples will be able to share parental leave. No longer will there be an assumption that women care and men work. And yet when it comes to allocating parental rights, the system has an in-built bias where men are regarded more sceptically than women, even with suspicion. There are some drastically unsuitable mothers out there, but the law generally views women as fit parents until proven otherwise, while unmarried men not lucky enough to be named on the birth certificate must shake off the taint of being inherently irresponsible. Those who fight for their rights talk of being seen as troublemakers in the eyes of law officers and social workers, as if they are pursuing a vendetta. Perhaps some are, but that should not discredit the many who just want to have a relationship with their child.
A century ago women had few rights when it came to their children. Then the importance of the mother-child bond was recognised and women started to be favoured over men. No doubt up until the 1960s, when illegitimacy was considered shameful, many men were relieved not to be named on the birth certificate, but the trend also had the inadvertent effect of turning some men into second-class parents. Today, half of children are born out of wedlock and it bears no stigma. Some fathers still shun their responsibilities, but others want desperately to be involved.
The need for a higher standard for fathers is at times defended on the grounds that the child might have been conceived in an abusive relationship. The strongest safeguards are needed to protect women and children from vicious low lifes, but it should not be beyond the wit of lawmakers to devise a system that builds in those protections without putting every other dad at a disadvantage in the process.
The gravest failure of the current system is in depriving children of relationships with their fathers. The importance of strong family relationships in producing secure, confident, optimistic children has become a guiding light in government policy on everything from improving health and boosting employment to reducing offending. A Ben Nevis of PhD theses has been written about the value of strong male role models, especially for boys. Children benefit from having a loving dad as well as a loving mum - who knew?
Mr Park wants both fathers and mothers to be recognised as parents provided they are fit and able to care for their child. What's wrong with that?