Under current Taiwanese legislation the father of a child born out of wedlock cannot appear on the ‘official’ Taiwanese birth certificate (the one written in Mandarin that is used for household registration), it doesn’t matter if your a foreigner or not, the same rules apply. You can however obtain an English version of the birth certificate for use in obtaining dual nationality status with your home country, it should be pointed out though that you may well be asked by your own government to produce supporting evidence as to the child’s paternity, i.e. a DNA test report. There are some quirks in the law though (as with most things Taiwanese), but they get very very messy and are much too lengthy to discuss here…
I know, I’ve got 2 children with my Taiwanese partner, fortunately we are a happy and settled family unit!!