The early Christians based the family on Jewish tradition which was based on (
Genesis 1:28) reflecting the mandate to “be fruitful and multiply”.
Paul also mentions that a church leader has to first be hospitable and manage his own household and family. The importance of bringing the family up in the faith. There were clear setups on how a family should be and conduct themselves.
Parents were instructed to teach their children the ways of the Lord, as seen in
Ephesians 6:4
Hospitality was a hallmark of early Christian homes, reflecting the biblical mandate to welcome strangers and support fellow believers.
Romans 12:13
Acts 2:46: Every day they continued to meet together in the temple courts. They broke bread in their homes and ate together with glad and sincere hearts,
Basically, Christianity made a struggling Roman family system better by changing the rules. Early Christian leaders called husbands and wives to a higher standard, telling fathers to treat all in the household kindly,
From my understanding the church has always looked upon the family as important. Especially promoting the traditional family of father, mother and children. The church certainly grew in families and this was the basis for western culture through the ages.
If anything it is modern ideas that have undermined the family. Women now put having kids and families lower than having a career. Along with the breakdown of the traditional family the birth rate seems to be falling.