The first indication we are given that family, birth and care are different in this story is when we are told that Jonas' father is a "Nurturer":
He and the other Nurturers were responsible for all the physical and emotional needs ot every newchild during its earliest life.
Clearly in this community mothers and fathers are not responsible for caring for their babies. Then, in Chapter 2, Jonas remembers when his family "received" Lily when she became one:
Each December, all the newchildren born in the previous year turned One. One at a time - there were always fifty in each year's group, if none had been released - they had been brought to the stage by the Nurturers who had cared for them since birth.
With this and other references to families having to "apply" to have children, we realise that we are in a very different society where children are made and born using "Birthmothers" - women who have been given that Assignment. They are then taken away and cared for by the "Nurturers" until they are one, when they are given to families who have "applied" to have children. As the novel progresses we realise there is very little choice in this world - even who you "marry" is chosen by the elders of the community. Thus children had no contact with their parents and were brought up in a world where they had very little choice.
Babies are born from Birthmothers, who, in some way never explained, become pregnant, give bith to 2 or more children in a course of 3 years, then become Laborers for the rest of their lives.
Infants are taken to be taken care of for a year. They progress (if not, they are Released or, in some very special cases, given another year) and are given their names and parents at the Ceremony.