There are many female saints.

St. Ada

Abbess and dedicated virgin, noted in France as a patroness of religious women. Ada was a niece of St. Engebert, the bishop who was murdered by his own cousin. Raised in a pious household and influenced by her uncle, Ada joined a convent in Soissons, France. She later became the abbess of St. Julien-des-Prés in Le Mans.

St. Agnes

St. Agnes of Rome was born in 291 AD and raised in a Christian family. Agnes was very beautiful and belonged to a wealthy family. Her hand in marriage was highly sought after, and she had many high ranking men chasing after her. However, Agnes made a promise to God never to stain her purity. Her love for the Lord was great and she hated sin even more than death!

Whenever a man wished to marry Agnes, she would always say, "Jesus Christ is my only Spouse."

According to legend, the young men she turned away became so angry and insulted by her devotion to God and purity that they began to submit her name to authorities as a Christian follower.

In one incident, Procop, the Governor's son, became very angry when she refused him. He tried to win her for his wife with rich gifts and promises, but the beautiful young girl kept saying, "I am already promised to the Lord of the Universe. He is more splendid than the sun and the stars, and He has said He will never leave me!"

In great anger, Procop accused her of being a Christian and brought her to his father, the Governor. The Governor promised Agnes wonderful gifts if she would only deny God, but Agnes refused. He tried to change her mind by putting her in chains, but her lovely face shone with joy.

St. Alfreda

Virgin and hermit, also known as Afreda, Alfritha, Aelfnryth, and Etheldreda. She was the daughter of King Offa of Mercia, in England, and was either betrothed to or loved by St. Ethelbert, the king of the East Angles. Ethelbert went to Offa's court to ask for Alfreda but was murdered by Offa's queen, Cynethritha. Horrified by the deed, Alfreda departed the court and retired to the marshes of Crowland. There she lived as a hermitess until her death. Her sister, Aelfreda, also lost a husband to the political intrigue of Offa and his queen.

There are many more if you go to http://www.catholic.org/saints/female.php.