Is semen pure or impure, and does pre-seminal fluid (madhiy) exit upon sexual arousal or normal thoughts, and does pre-seminal fluid (madhiy) invalidate ablution (wudu') if it is pure?

Semen (mani) is pure according to the Shafi'i and Hanbali schools, whereas pre-seminal fluid (madhy) is impure by scholarly consensus. The assertion that semen and pre-seminal fluid originate from a single gland is incorrect, as they differ in their characteristics, and impurity is not purified through transformation (istihalah). It is obligatory to wash off pre-seminal fluid and whatever it has contaminated on the body and clothes, and to perform ablution (wudu) for prayer. As for normal bodily discharges, they are pure but invalidate ablution, and it is not obligatory to wash clothes or the body from them. There is no difference between the pre-seminal fluid of a man and a woman. One afflicted with chronic leakage of pre-seminal fluid should perform ablution for each prayer after its time has begun.