yes thats right but one group is kept indoors while the others out, so i would say there is hardly any chance of tuan being father so it could be gordons first.
If Tuan and Amy are ever outside on opposite sides of a mesh fence, it could be his. However if Gordon lives with Amy, its more likely to be his. If the birth is successful, they could do a DNA test at a later stage if they really want to know.
Do Orang males play a role in family life?
No. Adult male Borneans are untrustworthy with infants- sometimes they will kill them. However, Sumatran males are less aggressive and more suited to group life- the males nearly always being tolerant of their offspring. Its said this could be a form of 'protective' behaviour of their family, stemming from the fact there are tigers in Sumatra, but not in Borneo...