  While many studies have shown a correlation between properties of the light
curves of Type Ia SN (SNe Ia) and properties of their host galaxies, it remains
unclear what is driving these correlations. We introduce a new direct method to
study these correlations by analyzing `parent' galaxies that host multiple SNe
Ia 'siblings'. Here, we search the Dark Energy Survey SN sample, one of the
largest samples of discovered SNe, and find 8 galaxies that hosted two likely
Type Ia SNe. Comparing the light-curve properties of these SNe and recovered
distances from the light curves, we find no better agreement between properties
of SNe in the same galaxy as any random pair of galaxies, with the exception of
the SN light-curve stretch. We show at $2.8\sigma$ significance that at least
1/2 of the intrinsic scatter of SNe Ia distance modulus residuals is not from
common host properties. We also discuss the robustness with which we could make
this evaluation with LSST, which will find $100\times$ more pairs of galaxies,
and pave a new line of study on the consistency of Type Ia supernovae in the
same parent galaxies. Finally, we argue that it is unlikely some of these SNe
are actually single, lensed SN with multiple images.
