May I point out:
Even in Israel--under circumstances that are different from those we know experientially, whose laws if they are preserved for us in their Constitution are useful to us only so far as the general equity in them demands--it was not an
absolute rule that the damsel should marry the man who seduced her.
Consider the parallel passage in Ex.22, esp.
v17:
16 “If a man entices a virgin who is not betrothed, and lies with her, he shall surely pay the bride-price for her to be his wife. 17 If her father utterly refuses to give her to him, he shall pay money according to the bride-price of virgins.
My point is not to avoid the reality that a child needs two parents, or that there isn't reasonable encouragement for the two parents to marry and create stability out of their confusion. Those are valid points.
But by initially running to an OT law to extract a
prescription, when that law is dead ("expired"), when this is a situation requiring
wisdom, when the laws of ancient Israel's Constitution themselves require comparison and wisdom in application--all this short circuits the path to finding the best answer to the plea of the original post.
The fact is that there could be many good reasons why this girl should not marry this man. Her parents could be dead set against it, and to pressure them to adopt a particular course solely because there was a law in ancient Israel that seems to speak to the situation (of which a full accounting shows more than was first presented) is foolishness.
The male youth could be someone who is now generally worthless as a provider and never will be what he ought, and the girl's father could be seeing the present reality and the future trajectory (not infallibly). The likelihood of the right suitor coming along later in today's world, who isn't only interested in a virgin (as preferred in ancient Israel, and perhaps still so now but to a lesser degree), is one reason why the parents might hesitate in taking on a son-in-law who has thus far proved dishonorable. Is he willing to marry for the right reasons, or because he too is being pressured to take on the responsibility?
Repentance may look like it includes going to the altar; but not necessarily. This is a situation that calls for looking carefully at many factors, and not rushing for a "solution" that ends up creating a worse condition than a pregnancy and child out-of-wedlock.