The midichlorian count was a controversial topic in Star Wars when it debuted in 1999’s The Phantom Menace, which brings us to Anakin Skywalker (Jake Lloyd). The mention, via dialogue from Liam Neeson’s Qui-Gon Jinn and Ewan Macgregor’s Obi-Wan Kenobi, that the future Darth Vader’s midichlorian count is obscenely high.
Obi-Wan doesn’t mention how high the Midichlorian count is for Anakin. But he indicates it is over 20,000, much higher than Grand Master Yoda’s. Qui-Gon reveals that everyone has Midichlorians in their blood. It’s heavily implied also that Anakin was conceived via the midichlorians.
Anakin’s twin children with Padmé Amidala, Luke Skywalker and Leia Skywalker Organa Solo would’ve had high midichlorian counts. But how high is unknown, at least in canon. Also, Leia’s son, Ben Solo, was also Force sensitive and, like his grandfather, uncle and mother, was strong in the Force.
Luke would learn about the midichlorian while researching the Jedi that existed during his father’s time. He would discover that midichlorian counts were used as a unit of measurement by the Galactic Republic Jedi. This was to determine how powerful a Jedi could potentially be.
Furthermore, it is possible that Luke might have used this to discover how powerful Ben would be and proceeded with caution. We all know how that turned out.
The Power Of The Force
Ben, unlike his grandfather, was known to throw Force-induced tantrums as a child. Leia also said she could sense her son switching between the dark and light sides during her pregnancy.
In conclusion, it is speculated that it has existed since Legends continuity that Padmé may have been Force Sensitive during her pregnancy with Luke and Leia.