The authors present the results of an econometric analysis of the factors of large families in the Russian Federation in recent years. Childhood as a social phenomenon is not homogeneous in its manifestations and can be implemented through various social practices and scenarios. An approach that explains large or small children through a triad of indicators: the average expected number of children, the average desired number of children, the average ideal number of children does not justify itself. The aim of this article is to analyse the factors that affect large children. Various socio-psychological, economic and other factors influence the decision on the number of children. The same factors may not have any influence on the decision to have, for example, the first child, but the decision to have the second or subsequent child will have priority. Conversely, some factors may be considered negligible when deciding to give birth to a first child, but these factors can have a significant impact on the decision to give birth to subsequent children. The analysis has made it possible to assess both changes in the behaviour of the population and the sensitivity of certain factors to the decision to have many children by region of Russia.