How do homeless children become homeless?

Actually, a child that gets abandoned usually ends up in foster care, not on the streets.

The National Center on Family Homelessness has compiled many facts on child and family homelessness. Under the title "Why Are Families Homeless" the NCFH writes:

"Family homelessness is caused by the combined effects of lack of affordable housing, extreme poverty, decreasing government supports, the challenge of raising children alone, the changing demographics of the family, domestic
violence, and fractured social supports. As the gap between housing costs and income continues to widen, more and more families are at risk of homelessness. For families with vulnerabilities or little safety net, even a seemingly minor event can trigger a catastrophic outcome and catapult a family onto the streets."

So children end up homeless mostly because of a lack of affordable housing, poverty and domestic violence.

Some older homeless children and teens are runaways, and according to the Invisible Youth Network, the reasons for running away can include abuse in the home, sexual violence in the home, and drug use in the home. A disproportionate percentage of runaways are also members of the LGBT community.

This is a complicated issue, but the complexity serves to remind that each child and teen on the streets has a story and is a human being with separate and unique reasons for their situation.