You do realize that until Churchill’s time... little boys wore dresses until age 3-4... and ribbons in their hair.
Had nothing to do with sex at all, children and babies were seen as pretty and angelic. Think about why baptismal gowns are unisex.
And...I’m pretty sure Churchill would have happily explained it had no effect on his manhood.
It had to do with the masses of padding required before waterproof diapering products were developed. Little boys got to wear pants when they were toilet-trained.