reg triple dummies interaction , omitted for collinearity , how to solve without changing base?

[Chiara Tasselli]

Good evening,

I would like to run the following regression:

 reg i.Time#i.TREAT#i.FEMALE [.covariates]

or

 reg i.Time##i.TREAT##i.FEMALE [.covariates]

The problem is that I am interested in the effect of treatment on females at time one, but of course, is omitted for collinearity... is there a way to change the display mode to omit something else instead of interaction?

I had also tried to put a male dummy instead of the female one, but I haven't solved my problem.
Many thanks in advance for your time and help!

[Fei Wang]

Chiara, you may estimate the treatment effect for certain cases using command -margins- after -reg-.

reg DV time##treat##female
margins, dydx(treat) at(female=1 time=1)