The days from conception to when a child reaches two are so important they "should be elevated to the same level as defence of the realm", a report in the UK has claimed.
The cost of failing to deal adequately with the mental health of mothers before and after birth coupled with the linked issue of child maltreatment has been estimated at £23 billion each year, the study said.
The report, which has been commissioned for the All-Party Parliamentary Group for Conception to Age 2, sets out a number of recommendations to help give children the best possible start in life.
"Without intervention, there will be in the future, as in the past, high intergenerational transmission of disadvantage, inequality, dysfunction and child maltreatment," the report said.
"These self-perpetuating cycles create untold and recurring costs for society. The economic value of breaking these cycles will be enormous.
"Recognising its influence on the nature of our future society, the priority given to the first 1,001 days should be elevated to the same level as defence of the realm."
Particular emphasis needs to be placed on fostering mental and emotional well-being, securing parental attachment and preventing child maltreatment, it added.
Among the proposals set out is the appointment of a Minister for Families and Best Start in Life, supporting relevant agencies to work together to prevent child abuse and making local authorities and health organisations prioritise all factors leading to the development of socially and emotionally capable children at age two "by adopting and implementing a 1,001-days strategy".
Children's centres should also become a central source of support for families in the early years with access to services including health visiting, GP services, housing, finance, parenting classes, birth registration, library and other community services, said the report, which follows a "1,001 Critical Days Manifesto" previously released by the group.
The cost of failing to deal with all these problems amounts to the equivalent of more than two-thirds of the annual defence budget, the study said.
In a foreword to the report, Tory MP and co-chairman of the committee Tim Loughton said: "The groundwork for good citizenship occurs in the first 1,001 days. A society which delivers this for its children creates a strong foundation for almost every aspect of its future. A society which fails to deliver it generates enormous problems for the future in terms of social disruption, inequality, mental and physical health problems, and cost.
"No section of society is immune. Deprivation may lead to a greater concentration of affected families, middle class mothers can be just as prone to perinatal mental health problems and the impact on their children. Certain groups, such as the families of armed services personnel, are a particularly high-risk section of the population yet go largely under the radar."
Susan Ayers, professor of maternal and child health at City University London who is also on the committee, said: "This report is long overdue. The evidence that pregnancy and the first two years of life are critical in a child's development and long-term health is substantial.
"To ensure the best start in life and good physical and mental health of future generations we need to support women during pregnancy and birth, and support families during the first two years of a child's life.
"The report shows that women's mental health is central to children's health and puts forward a number of recommendations that, if implemented, will reduce perinatal mental health problems and the transmission of vulnerability from one generation to the next."