Originally, knitting was consider a male trade. So what happened?
According to History and tradition of Mallerstang Forest and Pendragon Castle by William Nichols, knitting "was a universal occupation, both for men and for women". This painting from 1400's shows Madonna knitting while this drawing from 1800's shows a male shepherd knitting.
According to The Art of Fair Isle Knitting., in the 17th and 18th century knitting was a cottage industry for sheep rearing areas such as Scotland, therefore both men and women were involved in the effort. After the Industrial Revolution and the invention of knitting machine a large segment of the population are no longer dependent on knitting by hand to produce clothing. According to The Old Hand-knitters of the Dales, in addition in the 19th century knitting patterns, along with other small craft patterns, were increasingly marketed to middle class women so knitting became primarily a hobby rather than an economic choice.