I think there are many different indicators in the chart because there are infinite reasons a child may not know or meet their father. Infinite scenarios and circumstances so infinite potential aspects/placements in a chart.
I think there is likely to be some kind of Saturn/Neptune or Sun/Neptune or Sun/Pluto affliction. But that can come in many forms in the chart. Maybe Sun in the 12th or Sun conjunct Neptune or Saturn.
Maybe Sun opposed Pluto in the 12th, in cases where Father dies when child is young or not yet born...Saturn in 12th if father is in prison or hospitalized. Perhaps Neptune afflictions if Father is drug addict and never stepped up and tried to father the child?