http://en.wikipedia.org/wiki/Infant_and ... psychology
...http://www.cdc.gov/growthcharts/data/se ... 41c021.pdf (boys' height)
...http://www.cdc.gov/growthcharts/data/se ... 41c022.pdf (girls' height)
http://hypertextbook.com/facts/2003/Bro ... anar.shtml
Tropes aside, realistic children are generally weak as kittens compared to adults, in every aspect. The reason this is not immediately obvious to everyone is because Western civilisation has created customs where it is considered unacceptable for adults and children to compete directly against each other. There are very few cases where it is actually worth stating out children in a game.
if you want to play heroic children anyway, the simplest approach is to play as either a human (for older kids of about 13+) or halfling, use point-buy for ability scores, and avoid picking too high a Strength or Wisdom score.
As for realistic human children...
Height | Average Age 3 ft | 2.5 years 4 ft | 7.5 years 5 ft | 12.5 years
4 ft just happens to be the cut-off point between Small and Medium size. So we can make the following size categories based on ages. Numbers and size classes assume human standards. Adjust as appropriate for other game races.
Age | Age category | Size Class 0-1 | Infant (unplayable) | Tiny (20 inches at birth) 2-4 | Toddler (unplayable) | Small (2-3 ft) 5-7 | Child | Small (3½-4 ft) 8-12 | Preteen | Medium (4-5 ft) 13-14 | Teenager | Medium (5+ ft) 15+ | SRD Adult | (5+ ft)
Infants are unplayable, and generally helpless in any situation where they may be in danger. Toddlers (and infants able to crawl) are also able to get themselves into dangerous situations, and move out of prepared safe areas. They have no real capacity to learn, as the neural connections that allow for long-term memory have not yet formed. The learning that does take place is mostly learning basic muscle coordination, figuring out how to interpret sensory information, and speech. Remembering what you had for lunch last week is relatively advanced.
Of these four playable age categories, SRD adults need no further explanation. For other age categories, I'd apply the following. Note that none of these actually gain any bonuses to any ability score. While Dexterity might be expected to increase with smaller size, this is countered by the fact that the youth is still getting used to their new reach and height, and the rapid growth that comes with childhood rapidly renders any such understanding obsolete (the "gangly teenager" effect). Also note that the mental penalties reflect the fact that the brain has not yet developed the cognitive functions for advanced levels of thought, analysis, contemplation, deception, or other social interaction.
Child (5-7 years)
- Smaller: A child is considered to be one size class smaller than an adult of their race. This may affect natural AC according to this table, carrying capacity, and various other aspects as shown in this table.
- Slower: Shorter legs, yo. Children have a base speed of approximately 2/3 that of an adult. A base speed of 20 ft becomes 15 ft; 30 ft becomes 20 ft; 40 ft becomes 30 ft.
- -6 Strength, -4 Constitution, -4 Intelligence, -6 Wisdom, -4 Charisma. These ability modifiers replace those that may be gained from the size class change.
Preteen (8-12 years)
- Adult Size: A preteen is considered to be the same size class as an adult of their race.
- Slight Build: A preteen is considered one size class smaller for purposes of determining their encumbrance limit. If the race normally has powerful build, this is lost, but the character does not gain the slight build disadvantage as described here. Note that this is not the same as the WotC kobold race feature, which is strictly an advantage.
- -4 Strength, -2 Constitution, -2 Intelligence, -4 Wisdom, -2 Charisma.
Teenager (13-14 years)
- Adult Size: A teenager is considered to be the same size class as an adult of their race.
- -2 Strength, -2 Wisdom. A teenager has not yet grown into adult strength, nor do they have the wisdom that comes with maturity.