If no one minds yet another biological male weighing in on the subject:
Any decision to give birth or not (even before conception), certainly requires a great deal of genuine dialogue between partners. Together, you have to carefully consider not only the lesser concerns about whether an addition to the family can be financially supported, but the fact that you essentially have to make the most important choice of a person's life for them (the child's decision to be born). This must be considered because it will take some significant ethical commitment, care, and healing to mend that transgression.
Personally, I think of a true sexual encounter as something that should flow from love, and I have a strict sense of responsibility in the first place, so its unlikely that I'd ever find myself in this hypothetical situation. But that said, trying to come up with a hard principle to address every variant of such a situation (regardless of who your partner is, the nature of your relationship, what they want, what is best for the child given your mutual attitudes) is wrong-headed. This is a deeply personal (i.e. interpersonal) affair.
Let's say we're beyond the ideal scenario though. To somewhat oversimplify the situation, one might say that if the child is being objectified, if one or more parents are more concerned about themselves than the child or some sort of principle than the person they are talking about bringing into existence, and it seems unlikely that anyone will change by the time of birth - an early-term abortion may be a reasonable option (though such an act should by no means be taken lightly - each a tragedy born of our weaknesses). If one does go through the process of aborting a fetus, it had better be a transformative event - not one that happens twice if at all possible.
No, I don't believe that life in any truly meaningful sense begins at biological conception. A *child* is conceived through love; a "kid" is born through just the meeting of gametes. Still, between committing an absurd act of violence in abortion or cruelly throwing another person into the world with no intention of committing yourself to offering them a real family - neither answer is right if it does not bring serious transformation in the parents. If the child's immanent arrival does not transform a couple into a loving family, there can only suffering and hopefully growth in the would-be parents.
P.S. If my original answer became too unclear/confusing, I'm personally of such a disposition that I'm more likely to want to keep the child, but by no means would I consider my will the last word. My partner and I will consider each other's convictions as well as the potential child's welfare (in all its forms), and the possibility of our ethical debt to the child.
