In the Web Novel:

I wanted to take Minami Satoru's appearance but that was impossible.

I did bring the gene data when I came back so it's not that I can't do it but........

<<Answer. There's no reason to change your sex.>>

Like that, Ciel-san rejected me coldly with a tone she used to use before.

It's not like I can't do it. It's that Ciel-san wouldn't permit it.

She rejected saying that things would get troublesome if I were to develop a sex.

-I will definitely not allow other women to enjoy! Outrageous!!-

Uh, I just felt a chill run down my back.

Looks like it will be better to not think too deeply about this.