By the time he was one, Aidan Na could recognise and recite the alphabet.
And before he turned two, he could count up to 100 and speak in full sentences.
These days, the 3½-year-old is exploring complex polygons and 3-D shapes while his nursery mates are learning about basic shapes like squares and triangles.
Aidan's 37-year-old father, Mr Allen Na, who is a regional market-development manager in the life-sciences and biotechnology sector, said that his child's "quick development pace made us curious to know how he would fare in an IQ test".
Aidan's mother, Madam Vivian Yeo, is a clinical research manager in a pharmaceutical company.
Mr Na, who paid $600 for his son's IQ test, said: "(Aidan) would observe us unlocking our smartphones and memorise the password combination so that he could access YouTube to watch videos related to alphabets, shapes and numbers.
"He was even able to navigate the different channels with the search tool independently."
The test scores indicate that Aidan has an IQ of 142 - which is in the 99.7th percentile of his age group - his father told The New Paper on Sunday.
Dr Lian Wee Bin, paediatrician and neonatologist at SpecialKids Child Health and Development Clinic at Thomson Plaza, said that based on these anecdotes, Aidan's development is "unusually fast for his age".
"Kids in Singapore start to (recognise) letters and numbers when they are about two to three years old, though they often do not perfect it till later," she said.
The test Aidan took is one of three tests that Mensa, which touts itself as the largest and oldest high-IQ society in the world, recognises.
Called the Stanford-Binet Intelligence Scales, Fifth Edition (SB-5), testers say it works for kids as young as two to adults as old as 80.
Mr Na said he has applied for Aidan to join Mensa, but has yet to fill in the membership forms. A spokesman for Mensa Singapore confirmed that Aidan's IQ score qualifies him to join the society.
Aidan has a five-year-old sister, Charlotte. But unlike her brother, Charlotte was not tested by a psychologist, as her development milestones appeared to be in line with what are expected of children her age.
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