The discovery of $\gamma$-ray emission from some radio-loud narrow-line Seyfert 1 galaxies (RLNLS1s) indicated the presence of a relativistic beamed jet in these objects. This immediately opened a new question about their parent population: is how do they look like when observed at large angles? The study of the parent population has provided important new insights on the physical properties of this fascinating class of active galactic nuclei (AGN). In this work, I will review the most recent advances in the study of parent sources, and I will show the impact that a recent continuum survey carried out with the Karl G. Jansky Very Large Array had on this topic. Finally, I will show how all these new results point toward a new unification model for young jetted AGN.