When the Library of Congress named its annual 25 films to the National Film Registry for 2009, some of us noted that 5 of the titles were by women filmmakers. That's only 20%, but notably more than usual (e.g., zero in 2008).
But even advocates campaigning for more films by women on the Registry underestimated the number. While we could debate what screen credit one must have to be considered the maker of a film, for the moment let's use the conventional measure of director.
Of the 525 titles now on the National Film Registry, there are 31 directed or co-directed by women.
Of the movies directed by men, there are no doubt some that arguably had women exerting an authorial influence over the production. The group Women in Film and Television, for example, has been lobbying for films with influential women screenwriters. A good idea -- although I think campaigning for The Big House (the 1930 MGM prison film for which Frances Marion won an Academy Award as writer) is a bit odd. The redoubtable Frances Marion wrote 3 films already on the Registry: Mary Pickford's The Poor Little Rich Girl (1917), the Valentino picture Son of the Shiek (1926), and The Wind (1928, directed by Victor Seastrom and starring Lillian Gish). Since she has over 150 screenwriting credits, my guess other Marion films will get Registered down the line.
There are many more films deserving of the designation "culturally, historically, or aesthetically significant." The more we learn about the neglected cinemas of all stripes, the more surprises we find. It's too simple to say that women were/are historically not empowered to direct Hollywood feature films. Certainly recent research in silent-era film history has uncovered far more work by women directors than our generation previously thought. Why, then, presume we won't discover even more from other periods, especially if we consider all films of significance and not just theatrical features?