Hormonal 'minipuberty' influences the somatic development of boys but not of girls up to the age of 6 years.

Objective: Hormonal 'minipuberty' refers to a transient sex-specific surge of LH, FSH, testosterone (T) and estradiol (E2) in the first few months of life. We hypothesized a potential long-term effect of this hormonal surge on somatic parameters in the following years and therefore designed this longitudinal study.

Design: A hierarchical multiple regression analysis was used to analyse the potential influence of hormone concentrations during minipuberty on anthropometric measurements conducted in the first 6 years of life.

Sex hormone influence on human infants' sound characteristics: melody in spontaneous crying.

The specific impact of sex hormones on brain development and acoustic communication is known from animal models. Sex steroid hormones secreted during early development play an essential role in hemispheric organization and the functional lateralization of the brain, e.g.

Sex hormone testosterone affects language organization in the infant brain.

Using a phonological discrimination paradigm, we show that the brain responses of 4-week-old infants systematically vary as a function of biological sex and testosterone level. Females who are generally low on testosterone demonstrated a clear phonological discrimination effect with a bilateral distribution. In male infants this effect systematically varied as a function of testosterone level.