>You're making this into a business decision.

Well... that's the point. I really don't want to talk about it as an ethical decision, and I guess I can avoid that by pointing out that it is more obviously a good business decision. I'm sure Google put a lot of thought into this, but I'm also sure they put a lot of thought into the launch of Google Buzz. Unfortunately, the sheer amount of thinking that goes on doesn't guarantee success.

Of course, now you've cornered me, so I have to talk about it as an ethical decision. So, some things which pop into my head:

1 - the ability to not show your gender does not change the relative status of the genders in public perception (hereafter "gender inequality")

2 - the ability to not show your gender does diminish the importance of gender inequality w.r.t. setting up a Google+ account, i.e., inequality affects you less if you don't have to show your gender

3 - gender inequality is generally considered a bad thing

Per point (1), the negative consequences of allowing people to not show their gender are probably small, and per points (2) and (3), the positive consequences are probably significant. This means that people are probably better off being allowed to not show their gender.

But b'gosh, I've let yet another cat out of the bag by introducing the concept of "perceived risk" and claiming its existence.

Why do I think there is perceived risk?

Personal experience. If you haven't run into a sexism debate yet, you haven't browsed any serious technology forum with any sort of regularity. If, in a sexism debate, you don't see comments about men doing untoward things to women, you probably haven't read the debate very thoroughly. If there is a gorilla in a room, and nobody sees it, nobody talks about it; if there is no gorilla in a room, but everyone thinks they see a gorilla, people talk about it: people talk about what they see. I hear enough talk either from women complaining about creepy guys or from people talking about such complaints that I figure it is commonplace. In lieu of evidence I go with intuition, because at some point I have to make a decision.

I call it perceived risk because, in short form, people think that things they don't want to happen (anything from creepy private messages to violence) will happen if they show their gender. I'm trying not to accuse anyone of malice, negligince, cowardice or irrationality. Perhaps in some ironic twist this itself is cowardly.

So, from an ethical standpoint, I hope this is enough to justify allowing people to hide their gender.

There are many more questions: what risks are perceived, how do they come to be perceived, what risks are real, how do they come to exist, what are the effects of perceiving risk, how can real risk be prevented, and how can negative effects of perceiving risk be prevented, with an eye towards both valid and invalid perceived risk.

In an effort to broadly treat the last two topics:

It is progressively easier to take advantage of people who rank lower on Kohlberg's stages of moral development:

http://en.wikipedia.org/wiki/Kohlberg%27s_stages_of_moral_de...

An conception of the ideal of justice based on categorical imperatives (not necessarily in the Kantian sense) is not a guarantee of making the right decisions. However, it makes many decisions easier. It allows one to have sincere belief in their judgments about a situation, and to recognize irrational and unfair behavior before it has a chance of affecting oneself or others.

Compassion is excellent, but in too many cases trying to make a compassionate decision leads to feelings of uncertainty and powerlessness. Self-interest is necessary for survival, but in too many cases trying to make a selfish decision leads to feelings of isolation and unfairness. Laws are a necessary component of a free society, but they are written by flawed human beings, and often prescribe no choice at all or an obviously bad one.

Conversely:

Making decisions based on rationally chosen principles leads to a better situation for humanity as a whole. Contrast the success of the American revolution with the failure of the French revolution: George Washington adhered to the principles of justice and fairness and Napoleon did not.