[Heritability and environment in normal and abnormal development].

The environmental influence on human development can be studied by assessing similarities and discrepancies in developmental traits between biological and adopted siblings and twins, reared together and reared apart. Approximately 50% of total variance of general cognitive ability in a given population can be explained by the environment. This influence gradually decreases with age, from infancy to adulthood.

[Genetics of development and behaviour].

Quantitative genetics can make a significant contribution to disentangle the relative influence of genetics and environment on human development and its disorders. Estimates of Pearson s correlation coefficients between siblings, mono and dizogotic twins reared together or apart, allows the calculation of heredability, that is, the contribution of genetics to the variance of a given trait. In the case of many aspects of intellectual development, heredability is around 50%.

[A non invasive method for assessing sexual development at adolescence].

Introduction: Observational assessments of puberty that invades the adolescent's privacy are not acceptable for research in population groups. Results based on self assessment have been variable, and in many cases poor.

Objectives: To evaluate the validity of a questionnaire with simple questions addressed to assess early, intermediate and advanced puberty periods rather than specific stages.

[The development of the ethical thinking in children and the teaching of ethics in pediatrics].

The child's ethical thinking is not installed in his mind as a single act, but as a consequence of an evolving process. Kohlberg, based on Piaget's studies, described three main developmental stages: preconventional, conventional and post conventional. However, Vigostky and others emphasized the importance of the environment for the moral sculpture of children.