A main source for the ages
Predictors of early life milestones: Results from the Copenhagen Perinatal Cohort
Trine Flensborg-Madsen, Marie Stjerne Grønkjær, Erik Lykke Mortensen · 2019 · BMC Pediatrics
- Children
- About 4,000 children
- Where
- Copenhagen, Denmark
- Ages
- Up to 3 years (born 1959 to 1961)
- How
- When their child was 3, mothers were asked to remember the age their child first did each thing
- What it found
- Gave average ages for 20 milestones between 1 and 3 years. For example, children walked around the room on their own at about 14 months on average, drank from a cup with no help at about 17½ months and climbed stairs on their own at about 21 months.
- Limits
- Mothers had to remember back up to 3 years. Children who hadn't done something by age 3 couldn't be counted, so ages for later skills, like being dry at night, come out too early. The children were born around 1960, and babies born early were included.