No direct scientific link has been established — and BaZi doesn't claim one. Your BaZi chart is determined by birth time, not genetic inheritance. It's a temporal signature, not a biological one.
However, interesting correlations exist. Some researchers have noted that seasonal birth (which heavily shapes your BaZi chart) does correlate with certain personality traits and health predispositions in epidemiological studies. Winter babies and summer babies differ in measurable ways.
But BaZi works at the level of energetic archetypes, not molecular biology. It doesn't need DNA validation to be useful — it's a parallel descriptive framework, not a competing one.