[A.A. Cunningham]

Protestants have long believed in the Virgin Birth, but believe Christ had brothers and sisters that were conceived by more conventional means after His birth.

Contemporary Protestants perhaps but not Calvin, Zwingli or Luther, et al. They all believed in and taught of the perpetual virginity of the Blessed Virgin Mary.

[TXBubba]

I'm a Lutheran and we do not believe in the perpetual virginity of Mary. I don't think Luther believed that either.