We often think of a big, heavy baby as a sign of perfect health. But new data suggests those extra pounds at birth might leave a mark that lasts for years.

Scientists are trying to solve a mystery. Why are so many young adults getting bowel cancer today? They looked at the start of life for answers.

The study found a strong link between birth weight and gut health. It seems the way a body grows in the womb sets a path for the future. This "early programming" may change how cells grow in the colon.

What the evidence shows

• Heavy babies have a much higher risk of early bowel cancer.
• The risk applies to cancer found before the age of 50.
• Cases of this cancer in young people are rising across the globe.
• Body chemistry in the womb may trigger tumor growth later.
• Birth weight could be used to pick who needs early health tests.

THE BIGGER QUESTION

If our health is partly set before we even take our first breath, how much control do we really have? We spend billions of dollars telling adults to eat better and move more.

But this study suggests we should look further back. Should we be focusing more on the health of moms during pregnancy to protect the next generation?

WHAT HAPPENS NOW

Doctors might soon start asking patients how much they weighed when they were born. This simple number could help find people who are at high risk early in life.

It could change when people start getting colon tests. Instead of waiting until age 45, some people might need to start in their 20s or 30s to stay safe.

WHAT WE STILL DON'T KNOW

1. Does a mom’s diet during pregnancy change this specific risk?
2. Can a very healthy lifestyle as a child cancel out the risk from birth weight?
3. What is the exact weight number that should trigger an early cancer test?