Vtyjkyuk

Isn't の at the end considered feminine? Also, what should I use if I want to sound masculine or gender neutral?

See:

That chart is not incorrect but maybe a little misleading. Here's my impression (I dropped を and い because it's usually dropped in informal sentences):

• 何してるの？: gender neutral, very common


• 何してるんだ？: masculine, highly blunt, can be accusatory


• 何してるんだい？: masculine, gentle, mainly in fiction


• 勉強してるの。/ テレビ見てるの。: feminine, mainly in fiction


• 勉強してるんだ。/ テレビ見てるんだ。: masculine, blunt, mainly in fiction

In the real world, 勉強をしているの and 勉強をしているんだ are both uncommon. People usually simply omit の (e.g., "勉強。", "勉強してる。", "テレビ見てる。" as an answer to "何してるの？"). If they really need the nuance of の, they add something else after の/のだ (e.g., "勉強してるんだけど。", "勉強してるんだよね。", "勉強してんねん。 (kansai)").

I agree with the discussion at the link that DXV sent. I also agree with DVX's implication that the image you sent may be outdated. Please let me elaborate:

For the specific phrase:

何をしているの？

I think the tone of one's voice is more important than the actual use of の at the end. It is possible to say this in a masculine way, a feminine way, and a gender-neutral way, simply by modulating your voice.

I also think that the image is missing an important third possibility:

何をしているんだ。

This sounds masculine to me, and

何をしているんだい？

sounds like an older man.

Considering the image you sent, if I knew:

• There are two people


• One is a man and one is a woman


• Person A asked 何をしているの？ and Person B asked 何をしているんだい？

then I would say:

• It highly likely that Person A is the woman and Person B is the man


• It's quite likely that Person B is an older man.

However, this doesn't mean it is always possible to associate 何をしているの？ with a specific gender.

So I think an updated version of the image you sent might say:

何をしているんだい？ (likely an older male)

何をしているんだ　 (likely a young male)

何をしているの？ (male or female)

Using ん or の indicates a reason when giving an answer. An answer for a reason would end for "~のです" for "that's why...". ん is more common is spoken (informal) language and the です　is either omitted or changed to だ.

Thus the question "何なにしているの?" is asking the reason for "what are you doing?" or "what are you doing that for?". Notice that it gives emphasis in much the way as the phrase in English. Of course, this is also achieved with tone of voice. If you aren't sure which to use "何なにし[ている]LLH?" with a rising pitch accent is gender neutral.

It is acceptable for men to use the "feminine" forms at times but it is considered more blunt if women use the "masculine" form. Notice that feminine form more closely resembles the polite "何なにをしているのですか？" as it would be written. In general, using だ instead of です is more often used by men in Japanese.