University of Bristol says its Children of the 90s study is as important as ever.
The project is the most in-depth research into mothers and babies in the world.
Now the study is focused on observing multi-generational differences and patterns.
Most of the original Children of the 90s are now in their late 20s.
Participants have been extensively tested with their allergies, exercise levels, weight and other stats recorded regularly.
This led to the discovery that peanut oil in baby oils and creams can cause peanut allergy.
Children of the 90s has also resulted in shaping the medical advice given to people.
Mary Barbosa and Esther Ball took part in the original study and say it has affected how they handle babies.
Mary's son Christopher and Esther's daughter Josie are also part of the project.
Along with other 'Children of the Children of the 90s', they have been studied since 2012 to investigate multi-generational patterns.
Christopher and Josie have since got together and their own children are now being used to help learn more about family links.
Other medical breakthroughs from the study include the benefits of eating fish and the impact of glucose levels on pregnant mothers and their babies.
The project continues to grow and with more generations to study, University of Bristol are confident there will be more significant breakthroughs to come.