Uh...I don't think this artist considers it to be yaoi.

It has breasts. Whether or not this can be called genderswap is undetermined.

From Pixiv: 男女エロなので注意
[= As this is man/woman eroticism, be careful]

男女 means "man and woman"/ "androgyne" / "hermaphrodite".

I remember he(or she) using boku to refer to her/himself.

Wilfriback said:
I remember he(or she) using boku to refer to her/himself.

Rika of Higurashi uses boku too, and it's for sure that she is female xD

Though I like Leon more being a man XD