The book doesn't specify if the monster was created by one man or several or how he was brought to life. I think we can safely guess that the monster was brought to life using electricity because it has such an influence on Victor. SPOILER ALERT. I would also say that is safe to say that the monster was probably created using more than one man because later on Victor tears apart/destroys the monster's companion before he completes her creation. These are just my thoughts and if anyone has anything else they would like to add please comment
In 1815, shortly after the death of her first baby, Shelley recorded a dream that may or may not have had a direct influence on the plot of Frankenstein . On 19 March 1815 she recorded in her journal: "Dream that my little baby came to life again--that it had only been cold & that we rubbed it before the fire & it lived." Her anxieties about motherhood and the inability to give life may have led her to write the tale of the aspiring scientist who succeeds in creating a being by unnatural methods. For example, Frankenstein's act has been read, by Robert Kiely and Margaret Homans among others, as an attempt to usurp the power of the woman and to circumvent normal heterosexual procreation.