What is the developmental age in months for a child who walks independently, has an immature pincer grasp, speaks 4–6 words, and can identify two body parts?

Developmental Age Assessment: 15 Months

This child's developmental profile—independent walking, immature pincer grasp, 4-6 words, and knowledge of 2 body parts—is most consistent with a developmental age of 15 months (Answer C).

Motor Development Analysis

Gross Motor Skills

• Independent walking is the hallmark gross motor achievement expected by 15 months, and this child demonstrates steady independent walking, which aligns perfectly with 15-month expectations 1, 2
• Standing without support should be well-established by 15 months, which is consistent with this child's ability to walk independently 2
• In contrast, 12-month-old children typically walk while holding on but have not yet achieved fully independent walking 1

Fine Motor Skills

• An immature (developing) pincer grasp at 15 months is within normal limits, as the 2-finger pincer grasp is expected to be present but may still be refining at this age 2
• The classic triad of 12-month fine motor abilities includes mature pincer grasp, banging two blocks together, and placing a block in a cup 1
• By 18 months, children should demonstrate more advanced fine motor skills including scribbling and building a tower of 2 cubes 1

Language and Cognitive Development

Expressive Language

• Having 4-6 words at 15 months falls within the normal developmental range, as expressive language typically expands more dramatically between 15-18 months 1
• At 12 months, having 4 words including "Mum" and "Dad" represents the expected baseline 1
• The presence of 4-6 words indicates progression beyond the 12-month milestone but not yet reaching the more extensive vocabulary expected at 18-24 months 1

Cognitive Skills

• Knowledge of 2 body parts is appropriate for 15 months, representing emerging cognitive and receptive language abilities 1
• This skill demonstrates the child's ability to understand and identify specific concepts, which is consistent with mid-second-year development 1

Developmental Comparison Across Ages

Why Not 12 Months (Answer D)?

• At 12 months, children typically walk while holding on but do not yet walk independently 1
• The mature pincer grasp should be fully established by 12 months, whereas this child has an immature pincer grasp 1, 2
• The overall pattern of skills exceeds 12-month expectations 1

Why Not 18 Months (Answer B)?

• An 18-month-old should demonstrate more advanced gross motor skills including walking backward, running, and walking up steps with hand held 1
• Fine motor abilities at 18 months include scribbling and building a tower of 2 cubes, which are not mentioned in this child 1
• Language development at 18 months typically shows more extensive vocabulary than 4-6 words 1

Why Not 24 Months (Answer A)?

• A 2-year-old should be able to jump, ride toys without pedals, and build towers and trains with 3 blocks—abilities clearly absent in this child 1
• Language development at 24 months is substantially more advanced than 4-6 words 1
• The overall developmental profile is too limited for 24-month expectations 1

Clinical Reasoning

The American Academy of Pediatrics emphasizes that developmental assessment should consider the full pattern of skills across domains rather than isolated achievements 1. This child's constellation of abilities—independent walking (15-month milestone), immature pincer grasp (transitional between 12-15 months), 4-6 words (appropriate for 15 months), and knowledge of 2 body parts (15-month cognitive skill)—creates a cohesive developmental profile consistent with 15 months of age 1, 2.

The key discriminating feature is the combination of independent walking (which distinguishes this child from 12-month level) with an immature pincer grasp (which distinguishes this child from 18-month level, where fine motor skills should be more advanced) 1, 2.