A 22-year-old Falls City man faces a rape charge in Nebraska after marrying his pregnant, 14-year-old girlfriend across the border in Kansas.

Nebraska Attorney General Jon Bruning said Tuesday he charged Matthew Koso with one count of first-degree sexual assault in Richardson County. The felony is punishable by up to 50 years in prison.

"I'm not going to stand by while a grown man has a sexual relationship with a 13-year-old," Bruning said at a news conference, called primarily to discuss state crime statistics.

Koso could not be reached for comment Tuesday.

His mother, Peggy, defended her son's relationship with the girl. She said in an interview Matthew and the girl married May 3 in Hiawatha, Kan.

Koso faces the charge for a sex act that allegedly occurred before the marriage, when the girl was 13. She is now 14. The baby is due next month.

Peggy Koso is worried about how her son and his wife would handle the public scrutiny that will accompany the criminal charge, she said. Both already face an uphill battle, she said.

"This has definitely been a trying time for all of us," she said. "We're doing all we can."

The girl planned on eventually graduating from high school, she said. Matthew, she said, has a good job in Falls City.

"I don't see how the state of Nebraska can say that (it is illegal). They love each other very much. They're both excited about being parents."

Kansas law permits children 12 or older to get married with parental consent. Although Nebraska law prohibits marriage between those 16 and younger — even with parental consent — the state is still required to recognize valid marriages from other states, Bruning said.

Peggy Koso said the girl's mother consented to the marriage.

"The girl's mother said it was OK," she said. "She was aware they were friends."

The Journal Star does not identify victims of alleged sexual assaults.

"People don't believe a 14-year-old girl can be in love, but she is," Peggy Koso continued. "(Matthew) could have run when  he found out she was pregnant, but he did the right thing" and married the girl.

According to Peggy Koso, Richardson County Attorney Jeffrey Goltz decided against charging her son after he and the girl married.

Goltz could not be reached for comment Tuesday.

The attorney general's office could not comment Tuesday on why Goltz might have declined to charge Matthew Koso.

Bruning said at the news conference his office learned about the relationship from "citizens in Falls City who were shocked by it."

He said he was confident his office would get a conviction.

Nebraska law forbids sexual relationships between a person 19 or older and a person younger than 16.

"She'll be married to a guy who is in prison," Bruning said.

Reach Butch Mabin at 473-7234 or at bmabin@journalstar.com.

Kansas v. Nebraska

Kansas and Nebraska have differing laws governing when two people can get married. According to Kansas law, children 12 or older can get married with parental consent. Nebraska law, however, prohibits marriage between juveniles 16 and younger — even with parental consent. Yet the state is still required to recognize valid marriages from other states. Nebraska law also forbids sexual relationships between a person 19 or older and a person younger than 16.