The study pulls together research on health, education and poverty
Fewer children are living in poverty and academic achievement is rising, according to a report examining the well-being of young people in Wales.
But the major new study also found that a fifth of Welsh children under-15 are obese, and sexually transmitted infections are increasing.
The assembly government report is an attempt to pull together information on all aspects of children's lives.
Ministers hope it will act as a benchmark to help measure improvements.
Examining existing data on issues such as education, health and tackling poverty, it covers the lives of Welsh children from birth until the age of 18.
Children's Minister Jane Hutt said: "This is the first time we have published something which paints as comprehensive and reliable a picture of children and young people's well-being as possible.
As recession looms we are concerned that this may be used as a fig leaf for failure
Mark Isherwood AM, Conservative
"It highlights areas where we are making real progress, as well as the issues which still need our attention."
In health, it shows an increase in sexually transmitted infections and the high levels of teenage pregnancy in Wales compared with other European countries.
It also found that around a fifth of children under 15 in Wales are obese.
The number of children placed under care orders by local authorities has increased by around a third in the last decade, according to the report.
The study found that the vast majority are in foster care, with the most common reason being for neglect or abuse.
However, ministers have claimed some successes in tackling child poverty.
According to the report, 29% of children live in poor households. That is now on a par with figures for the UK, when previously it had been significantly higher.
There has also been a fall in number of homeless families with children, including those in temporary bed & breakfast accommodation.
In education, the figures show there has been a gradual improvement in the percentage of Welsh pupils gaining five or more GCSEs.
The report also found around 10% of 16 to 18 year olds were not in employment, education or training, which remains high by international comparisons.
The report and the ongoing monitoring was one of the commitments in the One Wales agreement that led to Labour and Plaid Cymru forming a coalition government.
Conservative spokesman on children, Mark Isherwood, welcomed the report but added: "As recession looms we are concerned that this may be used as a fig leaf for failure.
"Despite 16 years of economic growth we enter recession with almost 300,000 children in Wales living in families in poverty and almost one in five Welsh children living in workless households."
Liberal Democrat spokesperson, Eleanor Burnham, added: "Publishing an all-encompassing report on the state of our children's well-being is futile unless the Assembly government acts on these reports and statistics.
"Local authorities are the ones who have to deliver the majority of the assembly government's policies on child services however with this Labour-Plaid Government continuing to under-fund local authorities, it is no wonder children are still not benefiting from Assembly government policies."