Hadiths condemning female homosexuality
There indeed doesn't seem to be an explicit condemnation of female homosexuality in Quran, but some hadith sources suggest that the people of Lut and the people of Ras who were doomed because of their sins according to Quran had both male and female homosexuality among their transgressions.
Here I quote hadiths from Shia sources that corroborate the prohibition of same-sex stuff between women in very strong terms. The hadiths are issued by Shia Imams who are believed to possess the full, esoteric knowledge of Islam as either inherited from the Holy Prophet or granted by Jibril.
The first three hadiths are taken from the most important hadith source in Shia school, Kitab al-Kafi, set Foru al-Kafi, volume 6, chapter on "As-Sahq" (Arabic: "السحق" meaning female homosexuality or Lesbianism). The first hadith claims that once men of Lut fell into homosexuality, their women also followed their suit. The other two explain the painful Divine retribution that awaits Lesbians in hell. The last one also says that this practice has been taught to mankind by the daughter of Iblis:
٢-محمّد بن يحيى عن أحمد بن محمّد عن عليّ بن الحكم عن إسحاق بن جرير
قال: سألتني امرأة أن أستأذن لها على أبي عبد اللّه عليه السّلام، فأذن
لها فدخلت و معها مولاة لها، فقالت: يا أبا عبد اللّه! قول اللّه عز و
جلّ: زَيْتُونَةٍ لاٰ شَرْقِيَّةٍ وَ لاٰ غَرْبِيَّةٍ ما عنى بهذا؟
فقال: أيّتها المرأة! إنّ اللّه لم يضرب الأمثال للشّجر، إنّما ضرب
الأمثال لبني آدم سلي عمّا تريدين.
فقالت: أخبرني عن اللّواتي مع اللّواتي ما حدّهنّ فيه؟
قال: حدّ الزّنا، إنّه إذا كان يوم القيامة يؤتى بهنّ قد ألبسن مقطّعات
من نار و قنّعن بمقانع من نار و سرولن من النّار و أدخل في أجوافهنّ إلى
رءوسهنّ أعمدة من نار و قذف بهنّ في النّار. أيّتها المرأة! إنّ أوّل من
عمل هذا العمل قوم لوط، فاستغنى الرّجال بالرّجال فبقي النّساء بغير رجال
ففعلن كما فعل رجالهنّ.
Is'haq ibn Jorair said: A woman asked me to ask permission for her to meet Abi Abd Allah (pbuh) (Jafar us-Sadiq, the sixth Shia Imam from the bloodline of the Holy Prophet, credited
as founder of the Imami School), and I asked permission for her.... then the woman asked: Inform me about the ruling of [sexual affairs] between women and women?
He said: the ruling (i.e. the punishment) is that of adultery. Indeed when the Day of Judgement arrives, they are brought wearing pieces of fire, and they are worn with fiery scarves, and fiery pants, and with fiery shafts entering their stomachs towards their heads and they are thrown into fire. O women! The first to commit this act was the people of Lut, as when men pleased themselves with men, the women were left to themselves so they did together like what their men did to each other.
٣-عليّ بن إبراهيم عن أبيه عن عمرو بن عثمان عن يزيد النّخعيّ عن بشير النّبّال قال:
رأيت عند أبي عبد اللّه عليه السّلام رجلا فقال له: جعلت فداك! ما تقول
في اللّواتي مع اللّواتي؟
فقال له: لا أخبرك حتّى تحلف لتخبرنّ بما أحدّثك به النّساء.
قال: فحلف له.
قال: فقال: هما في النّار و عليهما سبعون حلّة من نار فوق تلك الحلل جلد
جافّ غليظ من نار عليهما نطاقان من نار و تاجان من نار فوق تلك الحلل و
خفّان من نار و هما في النّار.
... Bashir an-Nabal said:
I saw a man in the presence of Abi Abd Allah (pbuh) who said to him: May I die for you! What do you say about [sexual affairs] between women and women?
Then Imam said to him: I don't inform you about this unless you swear to inform women about what I say to you!
He said: And the man swore.
And the Imam said: the two are in the fire [of hell], and on them will be seventy layers of fiery clothes, and upon that all will be a dry curtain saturated with fire, and thereupon will be fiery belts and crowns on them, and fiery shoes and they will be in fire.
۴-عنه [علی بن ابراهیم] عن أبيه عن عليّ بن القاسم عن جعفر بن محمّد عن الحسين بن زياد
عن يعقوب بن جعفر قال:
سأل رجل أبا عبد اللّه عليه السّلام-أو أبا إبراهيم عليه السّلام-عن
المرأة تساحق المرأة:
و كان متّكئا فجلس فقال:
ملعونة الرّاكبة و المركوبة و ملعونة حتّى تخرج من أثوابها الرّاكبة و
المركوبة، فإنّ اللّه تبارك و تعالى و الملائكة و أولياءه يلعنونهما، و
أنا و من بقي في أصلاب الرّجال و أرحام النّساء. فهو و اللّه، الزّنا
الأكبر و لا و اللّه، ما لهنّ توبة.
قاتل اللّه لا قيس بنت إبليس ما ذا جاءت به.
فقال الرّجل: هذا ما جاء به أهل العراق؟
فقال: و اللّه، لقد كان على عهد رسول اللّه صلّى اللّه عليه و آله قبل أن
يكون العراق، و فيهنّ قال رسول اللّه صلّى اللّه عليه و آله: لعن اللّه
المتشبّهات بالرّجال من النّساء، و لعن اللّه المتشبّهين من الرّجال
... Ya'qub ibn Ja'far said: A man asked Aba Abd Allah (pbuh) or Aba Ibrahim (pbuh) (Musa al-Khadhim, the son of Jafar, and the seventh Shia Imam) about a woman having sex with another woman (the word used is
"مساحقه" translit. "musahiqa"). And he was leaning [when I asked
him] then he sat down and said:
The one who does this and the one to whom this is done are cursed, and
they are cursed until they take off the clothes that they had on when
doing this. And Allah the exalted and high, and the angels and His
saints curse the two, in addition to me and and whoever resides in the
backs of men and the wombs of women (i.e. the later generations). And
this act is, by Allah, graver than adultery, and by Allah, there's no
repentance for the two. May Allah kill Qais, daughter of Iblis who
introduced this [to humankind]!
And the man said: But this is what the people of Iraq have introduced!
And he (the Imam) said: By Allah it existed during the time of the
Prophet of Allah (pbuh) before it existed in Iraq, and the Prophet has
said about this group: May Allah curse those men who liken themselves
to women, and those women who liken themselves to men. (i.e. engaging
in things that has to be done with the opposite sex).
As for people of Ras, a hadith collection compiled by Muhammad Baqi Majlisi named Hayat al-Qulub draws very detailed accounts of the history and fate of this nation from different Shia Imams. According to one account given by Imam al-Kadhim, two doomed nations are associated with the name Ras (taken from the name of river Aras in Azerbaijan where they lived) who succeeded each other. The second nation faced Divine wrath because of adultery and female homosexuality.
Some philosophical reflection
Scholars of all sects agree that sexual activity between both men and women are prohibited in Islam. The rational wisdom must also be evident upon reflection. The very fact that we are created in opposite sexs that enable us to fulfill functions that are vital for human survival indicates that same-sex relations are immoral for they undermine those vital functions that are only fulfilled under heterosexual relations.
A deeper philosophical explanation can be drawn from Yin-Yang theory: Universe is made of opposite forces that complement each other by their interaction, giving rise to synthetic qualities that can not be without the underlying opposite forces meeting and acting on each other. The highest expression of this cosmic pattern is sexuality. Homosexuality is a violation of this cosmic pattern and detrimental to huaamnity for subverting the vital positive synthetic effects associated with it (including but not limited to reproduction). The next-worldly retributions talked about in religious sources explain the eternal consequences of violation of this cosmic law for the violators.
A similar explanation can be drawn from Islamic Sufism and Irfan. Men and women are considered to be manifestations of two opposite sets of Divine attributes known as Jalal (Majesty) and Jamal (Beauty). Jalal embodies other Divine names such as Qahar (Conqueror or Mighty), Malik (Owner), Qadir (Capable) whereas Jamal embodies names such as Latif (Gentle), Ghafur (Forgiving), Rahim (Compassionate). Note that these names represent ontological realities and are not just literal forms. Allah creates the creation by manifesting in them these names in different proportions and mixtures. From synthesis of these names, higher, fuller names emerge. Man is considered to be the noblest of creation for his potential to realize all Divine names. But on the level of worldly first nature, humankind is created in two distinct blends of Divine names, man and woman. When these opposite blends (or forms) of Divine names marry, as a result of many resulting synthetic processes on the physiological and psychological level between the distinct qualities in each sex, a higher level of ontological perfection and goodness yields for the couple, the most notable example of it being procreation. This may explain why Prophet Muhammad (pbuh) has said that "marriage is half of one's faith."
Critique of the idea of homosexuality "by birth"
The fringe phenomenon of "innate" homosexual inclinations must be seen only as deviations from man's God-given sexuality which can result from problems in upbringing or negative life experiences or even subtle irregularities in human psychological and psychological makeup by birth (provided that such inclinations do not proceed from willful homosexual behavior). Therefore the fact that one may feel good about such inclinations is not an indication that they are normal. In basic Islamic doctrine, there are clues indicating that moral vices similar to bodily health problems can be transferred via birth. A well-known example is the phenomenon of illegitimate birth which is believed in Islam to influence the moral inclinations of the resulting child.
Another potential factor in deviation from rightful conduct can be understood from Quran. Quran often talks about people who enjoy their sins and therefore engage in them because "Satan has beautified their sins in their eyes". In other words, man is always prone to find pleasure and norm in things that are immoral and abnormal because of satanic influences. These influences come in different forms and origins. According to doctrines of Muslim scholars of psychological ethics, the pleasure of sin is felt by man's body (in case of bodily sins) and by man's illusion (in case of more psychic vices such as arrogance) and the normality of all sins is induced by man's illusion, while the displeasure of sin is felt by the lamenting self (Nafs al-Lawwama) and the abnormality is recognize by human faith and illuminated intellect provided that they are not clouded by the dominion of the former inferior faculties.
Imbalance in human humoral makeup can also explain inclination towards bodily deeds that are regarded as sinful under Sharia according to the traditional Humoral medicine that is prevalent in the Islamic world among traditionalist scholars.
What to do with these inclinations?
According to what I’ve learned from Islamic psychology and traditional medicine, illegitimate inclinations can be eliminated by undertaking a sound bodily, mental and spiritual discipline, and depending on how deeply engraved they have become in one's bodily and psychological makeup, the remedies become more demanding. But the most basic and accessible bodily remedy I know of is fasting accompanied by the spiritual acts of worship since we know abstinence empowers human soul and by acts of worship soul can absorb spiritual perfections from Allah, helping it to reform the body after its normal archetypal form which is free from sinful inclinations. Heartfelt recognition of the philosophical explanation of sexuality that I laid out above can also be very helpful in reforming one’s sexual orientations and expectations towards its proper ontological end that is realized only under heterosexual relations.
If this guidance sounded too general and philosophical, tell me, I hope I can elaborate the wisdom in more concrete terms.