There's as much feminist literature as their are female writers.
There's only as much feminist literature as their are female writers.
ご質問ありがとうございます。
女性作家はfemale writerとかfemale authorと言います。「女性作家の数」はthe number of female authorsと言います。
そして、フェミニズム文学はfeminist literatureと言います。
ですから、The number of female authors is the amount of feminist literature there is.と言えますが、回答の英文の方が綺麗な英語だと言えます。
例文：「私の考えでは、女性作家の数だけ、フェミニズム文学があると思います」
In my opinion, there's as much feminist literature as there are female writers.
ご参考いただければ幸いです。
アメリカ合衆国 
