In Judges 11, there is a particular incident pointed to by Bible critics about God accepting a human sacrifice. Although the text may describe that, the best understanding is a conversion to perpetual virginity (not a human sacrifice):

Jdg 11:30 And Jephthah made a vow to the LORD, and said, “If You will indeed deliver the people of Ammon into my hands,
Jdg 11:31 then it will be that whatever comes out of the doors of my house to meet me, when I return in peace from the people of Ammon, shall surely be the LORD’s, and I will offer it up as a burnt offering.”

Jephthah was a mighty warrior and became judge of Israel for 6 years. When fighting Israel’s enemies, Jephthah gives a vow to offer the first thing he meets when returning from the conquest. He says he will offer it as a “burnt offering.” When returning home, he sees his daughter:

Jdg 11:34 When Jephthah came to his house at Mizpah, there was his daughter, coming out to meet him with timbrels and dancing; and she was his only child. Besides her he had neither son nor daughter.

One thing of note is that the text points out that this is Jephthah’s only daughter. Assumedly, the text to drawing focus to the fact that Jephthah is losing any chance at grandchildren. This is an interesting focus if Jephthah was going to kill his daughter. Although the point might be that his love was not split between multiple children, the text continues and focuses on his daughter’s virginity:

Jdg 11:35 And it came to pass, when he saw her, that he tore his clothes, and said, “Alas, my daughter! You have brought me very low! You are among those who trouble me! For I have given my word to the LORD, and I cannot go back on it.”
Jdg 11:36 So she said to him, “My father, if you have given your word to the LORD, do to me according to what has gone out of your mouth, because the LORD has avenged you of your enemies, the people of Ammon.”
Jdg 11:37 Then she said to her father, “Let this thing be done for me: let me alone for two months, that I may go and wander on the mountains and bewail my virginity, my friends and I.”
Jdg 11:38 So he said, “Go.” And he sent her away for two months; and she went with her friends, and bewailed her virginity on the mountains.

Jephthah’s unnamed daughter agrees to go along with Jephthah’s plan. She mourns her “virginity” for two months. Why does she not quick have relations with a man? What is stopping her from marrying a man quickly in order to solve the problem of her two months of mourning? Perhaps her real problem is that she does not have children? But the text seems to ignore that as her particular issue:

Jdg 11:39 And it was so at the end of two months that she returned to her father, and he carried out his vow with her which he had vowed. She knew no man. And it became a custom in Israel
Jdg 11:40 that the daughters of Israel went four days each year to lament the daughter of Jephthah the Gileadite.

At the end of the story the daughter returns to the father. Jephthah carries out his “vow”. The text then reads she “knew no man” (figuratively meaning she was still a virgin). Then the text describes women of Israel mourning her four days of each year.

At the time the vow was performed, there was not enough time to have a baby if she had gotten pregnant. The focus seems to be on her virginity, and not her childlessness. This seems to suggest that the “burnt offering” was not a literal burnt offering. Jephthah did not burn his child alive, but offered her as a spiritual burnt offering: “a perpetual virgin for the Lord”. This would fit the context. Jephthah is mourning not having grandchildren. His daughter mourns her virginity (and doesn’t solve the problem). Then the vow is coupled with his daughter still being a virgin.

Sacrifices seem to be used figuratively elsewhere in the Bible. In Phillipians, Paul describes a monetary offering as a burnt sacrifice:

Php 4:16 For even in Thessalonica you sent aid once and again for my necessities.
Php 4:17 Not that I seek the gift, but I seek the fruit that abounds to your account.
Php 4:18 Indeed I have all and abound. I am full, having received from Epaphroditus the things sent from you, a sweet-smelling aroma, an acceptable sacrifice, well pleasing to God.

In Genesis, Cain offers fruit as his offering (showing that all offerings were not necessarily death):

Gen 4:3 And in the process of time it came to pass that Cain brought an offering of the fruit of the ground to the LORD.

In Psalms, David describes his “broken heart” as an acceptable substitute for “burnt offering”:

Psa 51:16 For You do not desire sacrifice, or else I would give it; You do not delight in burnt offering.
Psa 51:17 The sacrifices of God are a broken spirit, A broken and a contrite heart— These, O God, You will not despise.

With these facts in mind, and the fact that God abhors human sacrifice (so much that it never thought Israel would ever do it), we can be safe assuming “a lost lineage” was Jephthah’s burnt offering. And this took the form of his daughter’s perpetual virginity.

Adam Clarke writes about the last sentence:

I am satisfied that this is not a correct translation of the original [Hebrew]. Houbigant translates the whole verse thus: …“But this custom prevailed in Israel that the virgins of Israel went at different times, four days in the year, to the daughter of Jephthah, that they might comfort her.” This verse also gives evidence that the daughter of Jephthah was not sacrificed: nor does it appear that the custom or statute referred to here lasted after the death of Jephthah’s daughter.