What makes someone Manglik
Mangal Dosha is formed when Mars occupies the 1st, 2nd, 4th, 7th, 8th, or 12th house. Most careful astrologers check this from three reference points — the ascendant, the Moon, and Venus — because the dosha is only meaningful if it shows from more than one. Mars in these houses is said to bring extra heat, drive, and friction into the marriage significations, which is where the reputation comes from.
Why it is so often cancelled
There are many recognised cancellations (Mangal Dosha bhanga): Mars in its own sign or exalted, benefic aspects, certain house or sign combinations, and — very commonly — when both partners are Manglik, in which case the doshas are traditionally considered to neutralise each other. Between the multiple reference points and the many cancellations, a large share of “Manglik” charts carry little to no real effect. The label is loud; the reality is usually quieter.
What it actually means for marriage
Where Mangal Dosha does operate, it tends to ask for maturity and the right match rather than to deny marriage — often showing up as delay or intensity, not impossibility. Read alongside the 7th house, the Navamsa (D9), and the dasha timing, it becomes one factor in a fuller picture of when and how marriage arrives, not a verdict on whether it can. This is exactly the kind of fear a real chart reading is good at right-sizing.