I know two to three instances where a sadhaka asks for a male child and the devatas offered a female child as a result of tapas.
#1: Manifestation of Draupadi
Although Drupada asked for only a son
O Yaja, perform that sacrifice by means of which I may obtain a son invincible in battle and capable of slaying Drona. Ready am I to give thee ten thousand kine
Draupadi also originated from fire. You can read it on the same page provided.
And there arose, after this from the centre of the sacrificial platform, a daughter also, called Panchali, who, blest with great good fortune, was exceedingly handsome.
#2: Manifestation of Savitri
Aswathi asked ma Savitri for a son, but ma Savitri bestowed a daughter of the same name (and then a hundred sons later)
Thereat Aswapati said, 'It is with the desire of attaining virtue that I have been engaged in this task. O goddess, may many sons be born unto me worthy of my race! If thou art pleased with me, O goddess, I ask for this boon. The twice-born ones have assured me that great merit lieth in having offspring!' Savitri replied, 'O king, having already learnt this thy intention, I had spoken unto that lord, the Grandsire, about thy sons. Through the favour granted by the Self-create, there shall speedily be born unto thee on earth a daughter of great energy. It behoveth thee not to make any reply. Well-pleased, I tell thee this at the command of the Grandsire.'
[291, Pativrata mahatmya Parva, Vana Parva, The Mahabharata]
#3: Manifestation of Meenakshi
Are there any other instances in which devatas bestowed a daughter even though the tapas is performed for a son only?