Whenever there is some great family event, or someone just wants to keep a memory alive, taking a few shots is what allows those who were not present to feel that they were part of the event. Of course, finding someone who can do this professionally is the key to having something which will last forever so check out 'family photographer' or 'baby photographer' online to see what is available.
With children, they pass milestone birthdays every year of course and relatives love to have a memory of this. Cute naked shots when they are tiny grow into carefully set shots amongst antique toys etc as they grow older. If you want to capture a unique family photograph then you can check out different photographer online.
But these are usually done by a professional who knows about dressing sets etc. Indeed, many will have special offers where they take a number of shots and they allow the relatives to choose which ones are to be enlarged to hang on walls or to adorn the home.
For group shots which include the parents and the kids, special techniques are used to keep the children all looking in the same direction or to get them to smile all at the same time. This may be difficult for the amateur to do since it does take some time and patience to get them in order.
Even weddings need someone who can control a crowd of individuals since most people get excited about seeing relatives that they have not seen for some time.