Chapter 17 of the novel Frankenstein the creature speaks to his creator, Victor Frankenstein, and says:
You must create a female for me, with whom I can live in the interchange of those sympathies necessary for my being. This you alone can do; and I demand it of you as a right which you must not refuse to concede.
After listening to this request Victor Frankenstein first became angry because he connected what the monster requested with the possibility of him striking again into acts of violence. However, the monster described itself as a creature worthy of love and as needful of it as any other living being. Victor was somewhat moved by this description and felt a sense of guilt. After all, it was he who was to blame for the creation of the monster. Was he also responsible for providing a quality of life for it?
The monster observed Victor’s hesitation and took that opportunity to appeal for his request with even more fervor. The monster even told Victor that, if he complies, he would move away from the rest of society with his female creature and never be in Victor’s life again.
This, Victor did not believe. He felt that the monster harbored too much anger within to not unleash its bitterness in the future. Therefore, he refused by telling the monster:
"You propose," replied I, "to fly from the habitations of man, to dwell in those wilds where the beasts of the field will be your only companions. How can you, who long for the love and sympathy of man, persevere in this exile? You will return, and again seek their kindness, and you will meet with their detestation; your evil passions will be renewed, and you will then have a companion to aid you in the task of destruction. This may not be: cease to argue the point, for I cannot consent."
In Mary Shelley's Frankenstein, the creature wants Victor to create for him a mate so he won't be so alone.
When the creature first makes his request, Victor flatly refuses. He believes the presence of a mate would allow the creature to be more dangerous than he already is by their sheer number. He could not release a second monster on society. He refuses to comply.
At first the monster gets angry and threatens Victor. However, he settles down and tries to logically reason with his creator. He entreats Victor to create another like him so that he is not alone. He uses sound reason, explaining that he is only violent because of how he has been treated. The creature promises that they will go far away and no one will ever see them again. Victor feels sorry for the creature and finally agrees to the monster's request. As the creature leaves, he warns Frankenstein that he will be watching him all the time to make sure he keeps his word.
"I swear," he cried, "by the sun, and by the blue sky of Heaven, and by the fire of love that burns my heart, that if you grant my prayer, while they exist you shall never behold me again. Depart to your home, and commence your labors: I shall watch their progress with unutterable anxiety; and fear not but that when you are ready I shall appear again."