There has been ongoing debate over the existence of true gender differences in handwriting dating back to the 1930s, however, when tested, children and adults can typically correctly identify the gender of the writer.
Sources: H. Tenwolde (1934). “More on sex differences in handwriting”; J. Hartley (191). “Sex differences in handwriting: A comment on Spear”; W.N. Hayes (1996). “Identifying sex from handwriting”; D. Lester, S. McLaughlin, R. Cohen, & L. Dunn (1977). “Sex-deviant handwriting, femininity, and homosexuality”; J.R. Beech, & I.C. Mackintosh (2005). “Do differences in sex hormones affect handwriting style? Evidence from digit ration and sex role identity as determinants of the sex of handwriting”.