Is Female Masturbation Evil?

I'm not clear why masturbation is still seen as wrong by religious orders. I realise the story of Onan in the Bible is used to condemn masturbation and, by the Catholic Church, sex without procreation. [Which to me smacks of a supposedly loving and merciful god killing two people for having independent thought.] However, biblical scholars view the killing of the two brothers Onan and Er to be an eponymous etiological myth - i.e. it didn't really happen as described, but is really meant to allude to the dying out of a clan. I'm no biblical scholar, but that to me rules out the connection between Onan and masturbation.

I'm not keen on the word evil, as I believe that all human actions are performed in an attempt to meet universal human needs (e.g. love, autonomy, independence, trust, honesty, etc. - for a full list, I overwhelmingly recommend the life-changing book Non-violent Communication: A Language of Life by Marshall B. Rosenberg Ph.D.); however, the strategy used to try and meet those needs may be tragic. For clarity, I'm not condoning anything that harms people (murder, rape, theft, etc.), I'm simply saying that I don't think labelling these actions as evil is helpful. I realise this is a radical way of viewing the world, so if you're interested, I recommend reading Rosenberg's book (above).

So, coming from this angle, we can simply ask, "Is masturbation harmful to me?"

Let's take a look:

Does masturbation cause physical harm?
No.
Contrary to popular myth, masturbation does not make you go blind or insane, cause acne, or make hairs grow on the palms of your hands.
In reality, the opposite is true - masturbation is physically good for you. It improves immunity, increases circulation, helps you to relax, and releases feel-good hormones into the bloodstream.

Does masturbation give rise to sexually transmitted diseases?
No.
Masturbation is the safest form of sex. You can't transmit any kind of STD to yourself from masturbation, unless you're already infected. For example, if you have a cold sore on your mouth (oral herpes), don't touch it and then masturbate without washing your hands first, as you'll give yourself genital herpes (for the same reason, don't give your partner oral sex if you have a cold sore).
You also can't get pregnant from masturbation, which makes me wonder why it isn't included in all of the sex education programs.

Will masturbation prevent you from enjoying sex?
No.
Masturbation can help you to enjoy sex more; the more you learn about what turns you on and what doesn't, the easier it'll be to convey to your partner what you do and don't like. Meaning, the more you understand what makes you come (and, just as importantly, what prevents you from coming); the more likely you are to orgasm.

Is masturbation harmful to anyone else?
Unless you're masturbating in front of a minor, or inflicting the act upon an unwilling adult viewer, we can't see how it can be harmful to anyone else.