The paternal instinct - you might think that it should exist, by analogy with the maternal instinct. In fact, nature did not take care that fathers were worried about offspring, but in human society, the family is built on the principles of love and mutual care, so we can say that the "paternal instinct" still exists.
What can be called the paternal instinct
Despite the fact that nature does not provide for the paternal instinct, there are some patterns of behavior that can be called that. Certain qualities are inherent in people, since they grew up in society, and social norms were absorbed by them from childhood. Single fathers exist, and they cope with raising children as well as single mothers, although this is less common.
The difference between the paternal "instinct" from the maternal is that it is based on rational actions, while women act rather intuitively. Some psychologists generally refuse to talk about this phenomenon, preferring not to use the word "instinct" in relation to paternal love. It is difficult to argue with this position. Nevertheless, cases of manifestation of paternal care for offspring are observed even in nature, which nevertheless allows us to speak of some instinctive inclinations. For example, in penguins, fathers hatch eggs, and this lasts for several weeks! During this time, penguins lose up to 40% of their body weight, which is about 5-6 kg. It is difficult to call this behavior a meaningful concern; rather, it looks like an instinct. Although the case of penguins is rare in nature, it might still be worth calling it the paternal instinct.
How the paternal instinct awakens
If in women the instinct of procreation is laid down by nature and often determines the inclination to certain actions, the desire for fathers to have offspring and take care of them wakes up with time. Family psychologists explain it this way. At the first stage of the relationship, a young couple tries to adapt to each other. People build a way of life that would suit both of them, because before that they lived separately and did not have to reckon with the desires and needs of each other.
Then they have a child. This is the third person! He is still quite small, but he is already showing his individuality, he needs constant care and attention. This responsibility is a difficult test for a young family, since the rules that have just been worked out are crumbling. The young father has conflicting feelings. The woman becomes a little aloof, the child absorbs all of her attention. At first, a man is uncomfortable, he usually tries to avoid paternal responsibilities. But time passes, and he notices how much the baby looks like him, starts talking to him, notices that the child is interesting as a person. Many fathers begin to truly love and care for their children when they are 2 or 3 years old. Before that, they are simply afraid of children, this is exactly the conclusion that psychologists have come to.
Interestingly, the love of mothers and fathers manifests itself in different ways. Women are more likely to smile at babies, and fathers are more likely to take children in their arms. Mothers love long conversations with their children, and fathers love playing together, like soccer or making something with their own hands.