Among the patients with prediabetes, how many are female?
patients with prediabetes refer to PATIENT from conditions where DESCRIPTION = 'Prediabetes'; female refers to gender = 'F';
SELECT COUNT(DISTINCT T2.patient) FROM conditions AS T1 INNER JOIN patients AS T2 ON T1.PATIENT = T2.patient WHERE T2.gender = 'F' AND T1.DESCRIPTION = 'Prediabetes'