 In 1993 , Feldman reworked his ideas into a <unk> script . This was sent to producer Frank Mancuso , Jr . , who had hired Feldman to adapt Sidney Kirkpatrick 's A Cast of <unk> . The producer got attracted to the creative <unk> as the film offered " the challenge of walking that fine line between <unk> and pushing something as far as it can go . " Metro @-@ Goldwyn @-@ Mayer got interested on the project , and while Feldman had some initial disagreements on the budget , after considering other studios he signed with MGM . In turn , the now retitled Species attracted director Roger Donaldson , who was attracted to its blend of science fiction and thriller . The script underwent eight different drafts , written over an eight @-@ month period , before Donaldson was content that flaws in the story 's logic had been corrected . At one point another writer , Larry Gross , tried his hand with the script , but ultimately all the work was done by Feldman . Feldman would remain as a co @-@ producer . While the initial Species script suggested a love triangle between Sil and two government team members , the dissatisfaction of the crew eventually led to changes to the ending , which ended up featuring Sil having a baby that would immediately prove dangerous . 
