Length to unlock:You will get this about 5-15 minutes into the game depending on if you are exploring and solving puzzles on your own, or if you are just using a walkthrough.
Difficulty:No skill required
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After activating the generator and finding the Gate key, you will unlock the gate and be able to progress, which will unlock the following trophy:
You will then be able to see some mobile homes/trailers straight ahead in the distance. Walk towards them and then to the upper back right area, where there are bathroom stalls, one of them has an item that you can look at in the toilet. Activate the pregnancy test and the trophy will unlock.
Alternatively, there are video solutions for those who prefer a visual--
Video 1: Shows the trophy unlock
Video 2: Shows a full trophy walkthrough for the entire game