It is due to gender roles within labor division in society. Civilization has the male gender preoccupied with farming, wars, governance and technology, and the female gender with offspring nurture, household labor and assist men with their labor. During industrialization of modern societies women have been added to factories to help with manufacturing, but this was to assist what was/is mainly male gender assigned economic sector. Society needed them to help in production but not diverge from their main social roles. Due to this women were paid less for the same unskilled or low skilled job compared to men in the same factory.
As a cumulative result, today women still attend less technical schools and subsequently are less involved in technology creation and innovation. Engineering is still a male stronghold today. Most women are alocated in the service industry (private or public sector), to assist men rule the world, because it is less physically demanding and leaves them time for their main societal roles. With or without men in the family, women continue to be assigned for offspring nurture, household labor and assist men with their labor.
So if the boys bother with technology, some of their everyday hobbies will revolve arround it. Girls are welcome, of course, but I don't see many of them rushing through the unlocked doors anytime soon.