The age-gap and gender do matter! The effect of gender and age difference between siblings on educational achievements
Abstrakt
The effects of birth order on human personality have been extensively studied. Here, we focused on the effect of siblings' gender and their age-gap on educational achievements.
We collected birth order data from university students using a questionnaire and computed the proportions of firstborns in two-child families (N=1110) considering age-gaps and gender composition. We found a significantly higher proportion of firstborns comparing Czech general population.
The firstborn proportion was strongly dependent on age-gap between siblings and their gender. If the siblings were of the same sex, the highest firstborn proportion was if the age-gaps were small or big and lowest if the age-gaps were medium.
If the dyads were consisted of opposite-sex siblings, the trend was reversed. Our results highlight the importance of controlling for gender and age-gap among siblings.
We further suggest to employ the above reported approach for testing the effects of birth order on other characteristics.