Purpose: The authors of this article examined the etiology of developmental language impairment (LI) at 4 and 12 years of age, as well as the relationship between the 2. Method: Phenotypic and quantitative genetic analyses using longitudinal data from the Twins Early Development Study (Oliver & Plomin, 2007) were conducted. A total of 2,923…

The present study is the first long-term longitudinal examination of the etiology of individual differences in language from early childhood through to adolescence. We applied a multivariate latent factor genetic model to longitudinal data from the Twins Early Development Study in order to (a) compare the magnitude of genetic and environmental…

The genetic and environmental origins of individual differences in mathematical self-evaluation over time and its association with later mathematics achievement were investigated in a UK sample of 2138 twin pairs at ages 9 and 12. Self-evaluation indexed how good children think they are at mathematical activities and how much they like those…

A previous paper in this journal revealed substantial genetic overlap between the ADHD dimensions of hyperactivity-impulsivity and inattentiveness in a sample of 8-year old twins drawn from a UK-representative population sample. Four years later, when the twins were 12 years old, more than 5,500 pairs drawn from the same sample were rated again on…

Purpose: In the 2nd decade of life, language skills expand in both quantitative and qualitative ways. The etiology of these new skills and the relationships among them have been little explored. Method: Taking advantage of widespread access to inexpensive and fast Internet connections in the United Kingdom, we administered four Web-based measures…

Purpose: To examine the etiology of the relationship between preschool speech and language, and later reading skills. Method: One thousand six hundred seventy-two children from the Twins Early Development Study (B. R. Oliver & R. Plomin, 2007) were given a comprehensive speech and language assessment at 4 1/2 years. Reading was assessed at 7, 9,…

During childhood and adolescence, increases in heritability and decreases in shared environmental influences have typically been found for cognitive abilities. A sample of more than 2,500 pairs of twins from the Twins Early Development Study was used to investigate whether a similar pattern would be found for science performance from 9 to 12…

The goal of this first major report from the Western Reserve Reading Project Math component is to explore the etiology of the relationship among tester-administered measures of mathematics ability, reading ability, and general cognitive ability. Data are available on 314 pairs of monozygotic and same-sex dizygotic twins analyzed across 5 waves of…

Background: Are there sex differences in the etiology of high performance in science in childhood that could contribute to the under-representation of women in scientific careers? In this study the relative contributions of genetic and environmental influences on high performance in science in both boys and girls were assessed using standard twin…

We investigated for the first time the genetic and environmental aetiology behind scientific achievement in primary school children, with a special focus on possible aetiological differences for boys and girls. For a representative community sample of 2,602 twin pairs assessed at age nine years, scientific achievement in school was rated by…

Using a genetically sensitive design, we investigated the etiology of academic performance in Science in elementary school, and its etiological links with other academic abilities and general cognitive ability ("g"). The sample consisted of over 2000 pairs of twins at 10 years of age from the Twins Early Development Study. Science performance, as…

This article explores how different raters have different strengths and weaknesses. Parents know their children well, but have a narrower framework on which to base their judgments about behavior problems. Moreover, in some cases such as hyperactivity, they are prone to exaggerate differences between their children. Teachers have greater expertise…

Purpose: The contribution of genetic factors in the persistence of and early recovery from stuttering was assessed. Method: Data from the Twins Early Development Study were employed. Parental reports regarding stuttering were collected at ages 2, 3, 4, and 7 years, and were used to classify speakers into recovered and persistent groups. Of 12,892…

Background: Impairments in language and communication are core features of autism spectrum disorders (ASDs). The basis for this association is poorly understood. How early language is related to each of the triad of impairments characteristic of ASDs is also in need of clarification. Aims: This is the first study that aims to determine the extent…

The genetic and environmental etiologies of 3 aspects of low mathematical performance (math disability) and the full range of variability (math ability) were compared for boys and girls in a sample of 5,348 children age 10 years (members of 2,674 pairs of same-sex and opposite-sex twins) from the United Kingdom (UK). The measures, which we…