By their 18th birthday, the average child has taken around 189 million breaths and walked over 75 million steps. If you're wondering whether your child is at the right stage for their age, you'll find the answers here.

Pregnancy Timeline
For your child's development in the womb, week by week, click here.

0-1 Your baby's development
The first hours of life
The first month
2-3 months
How your baby grows
Giggling & grabbing
Sounds & words
Responding to the world
4-6 months
Food, teeth & speech
Gaining more control
A world of wonder
Fascinated by people
7-9 months
Growing fast
Pre-speech communication
Learning cause & effect
Strong feelings
Attachment
10-12 months
First words
Up and about
Copycat
Laugh and play

1-4 Toddler Development
12-18 months
Growing up
Hello world!
Speech & vocabulary
Independence
Dependent/independent
18-24 months
Time for toilet training?
Running and tumbling
Understanding & speaking
Learning new stuff
The Terrible Twos
2-3 yrs
Running and jumping
Everything under control
Why...?
Speaking and stuttering
A sense of self
Making friends
Leaving babyhood behind
Accidents can happen
Learning and remembering
Emotional changes
Sense of right and wrong

13+ Teenage development
13-15 yrs
Changing bodies
Expanding minds
Pushing against authority
Emotions and family relations
Friends and romance
15-17 yrs
Physical changes
Girls and their bodies
A mind of their own
Teenage social life
Sex and relationships
18+
Joining the grown-ups
Life starts here?