Task: Question Answering
Input (English): Passage: Steve and Frances Howard are a middle-aged, married couple unable to have children together. They have discussed adoption but made no decision: the subject is clearly difficult for them. They have purchased a large detached house on a newly-built luxury estate in Middlesex, England, and are starting to furnish and decorate it. Also to attend to the extensive, but empty, garden. She teaches English to GCE A-level students, he is a sales executive in an electrical appliance company, enjoying the regular driving his job entails.
Steve picks up a free-spirited teenage hitchhiker, Ella, and has a brief affair. To his considerable shock and surprise Ella turns up at his home whilst he is away and introduces herself to his wife Frances. After they become acquainted over several bottles of wine, she claims to be pregnant by another man, then begs to be allowed to stay for the weekend. Calculating and manipulative, when Steve returns and Frances is away Ella threatens to abort the baby, which she reveals is his. He begs her not to, but she refuses. Torn between his faltering love for his wife, his infatuation with Ella, and his unborn child, Steve finally agrees to leave his wife and set up home with Ella to have the baby together. Ella agrees, though without much enthusiasm, but specifies he should tell his wife when she (Ella) is not present.  
Frances clearly suspects a secret relationship; her situation is further complicated by visits to her elderly mother, an emotionally repressed women who reveals the philandering nature of Frances' father. And how she endured their lifetime of marriage, and his habit of bringing lady 'friends' to their home, by shutting her mind to it. Frances discloses somebody her husband met, a young girl, is now staying with them. Resignedly, her mother tells her, 'You'll learn to live with it...'. 
Question: Who is the father of Ella's baby?
Output (English): Steve.