(1) The legal effects of acknowledgement may, unless the statute leads to a different conclusion, be asserted only from the date on which the acknowledgement becomes effective.
(2) An acknowledgement of paternity is not effective as long as the paternity of another man is in effect.
(3) An acknowledgement subject to a condition or a stipulation as to time is ineffective.
(4) The acknowledgement is admissible even before the birth of the child.