13/05/2016 11:02 BST | Updated 13/05/2017 06:12 BST

Anti-Mothers, Uber-Mothers, Passive Mothers and the Making of Murderers

Through examining 10 cases in Murderers and their Mothers, I have begun to unpick the complex fabric of the killer by pulling at the "mother" thread. Why such an emphasis on mothers? What about the fathers? Isn't this sexist? These are questions that I have encountered a lot over the past few months.

Murderers are not simply evil aberrations who come into the world as homicidal ticking time bombs. Creating someone able and willing to take the life of another is a complex and lengthy process, in which a number of factors, individuals, groups and institutions play a role. Biology matters. Families matter. Communities and neighbourhoods matter. Schools, prisons and health services matter.

However, one particular actor in the story of murder requires a closer look. Through examining 10 cases in Murderers and their Mothers, I have begun to unpick the complex fabric of the killer by pulling at the "mother" thread.

Why such an emphasis on mothers? What about the fathers? Isn't this sexist? These are questions that I have encountered a lot over the past few months. I argue that mothers matter more in the making of murderers because of the inherently gendered nature of society. We expect mothers to be selfless nurturers and primary caregivers - expectations we take for granted and apply to all. We defer to mothers, simply assuming that they know best and are prioritising the needs of their child, protecting them from harm both within and outside of the family. As long as mum is on the scene, surely everything will be alright?

Not in the cases that have been examined in the series - Daniel Bartlam, Fred and Rose West, Jed Allen, Harold Shipman, Dennis Nilsen, Robert Black, Joachim Knychala, Leszek Pekalski, Adam Lanza and Richard Kuklinksi. To varying degrees, whether by act or omission, the mothers of these killers began to write the script for murder.

The mothers of the Fred West, Black, Knychala, Pekalski and Kuklinksi created environments where brutality was every day and expected. They actively abused or neglected their children, creating deviant value systems in which the abnormal became normal. The mothers of Shipman and Lanza strove to cope with the circumstances that life threw at them. Wanting the best for their children, they encouraged their sons to be like others, hoping they would grow up to be men who looked and acted like other men. Through hypervigilance they tried to be the good mothers that society demands, being selective in the advice that they took on board from outsiders. The mothers of Bartlam, Nilsen and Rose West were in denial - looking the other way, unwilling to confront or discuss behaviours or abuses that might lead to their children being labelled as 'different', square pegs in the round role of mainstream society.

It is clear from this analysis that three types of mother make a murderer - anti-mothers, uber-mothers and passive mothers.

For anti-mothers, problems begin within the family. They are often the victims of abuse and neglect themselves, survivors of brutal upbringings who never experienced a healthy family environment. Not all women who experience violent families will go on to recreate abusive homes. They are more likely to harm themselves than others, internalising their trauma as they struggle to wrestle back the control they never had as children. But a few women will repeat the cycle. These are the women for whom templates for family life have never been rewritten - their extended families and communities often reinforcing their experiences or denying them altogether. They turn from victims of brutalization to ruthless aggressors - the same kind of aggressors they had once despised.

For uber-mothers, problems begin outside of the family. They come from relatively stable, if not "traditional" nuclear family environments. However, they become acutely aware of society's expectations of families and motherhood from an early age. They are the victims of a discriminatory and arbitrary moral framework in which their families of origin fail to come up to scratch. As mothers, they are determined that their children will not be restricted by the same labels they believe held them back - illegitimacy, poverty, minority. They become mother-managers who carefully chart the childhood and adolescence of their sons and constantly struggle to keep them on course. They are the gatekeepers that hold off the outside world, protecting their child from scrutiny as their behaviour becomes increasingly deviant.

Passive mothers fear the judgement that society may impose on their children. These mothers have lived out their lives following the rules, not crossing the lines, fulfilling social expectations. They have always been quiet, passive, just ticking along. Therefore when their children begin to bend the rules and cross society's moral and legal boundaries the fear of labelling compels them to respond in the only way they know - denial and inaction. Sweep it under the carpet. It will go away. It's a phase. They will grow out of it.

Anti-mothers, uber-mothers and passive mothers thrive because of the considerable cultural value society places on privacy. How mothers bring up their children remains largely "none of our business". Most children from disadvantaged families who experience maltreatment never come onto the radar of social services. The middle class family is largely beyond reproach, protected by neoliberal concepts of freedom, independence and self-sufficiency. Privacy can be valuable as it allows us to restrict who has access to our family places and spaces and enables us to control who knows what about our families. However, it can also be the barrier behind which violence, abuse, neglect and denial can thrive - and the making of a murderer can begin.

Murderers and Their Mothers, CBS Reality, Sundays, 10pm