Parenting: House rules and sex lives: Parents who are uncomfortable with their children's love lives should remember - it's not about morals but about respect for house rules, writes Louise Holden

An old friend of mine has lived with her boyfriend in England for three years. They recently came home to visit. On arrival at her parent's house, she was surprised when her boyfriend would not share her bed in the family home. She related the story to a table full of thirty-somethings and four out of the six took his side.

Having sex in your parents' house has been an uncontested taboo since economic progress gave newlyweds the option to set up new homes. Not that people waited until marriage to have sex, but no matter how sexually precocious you were, you still didn't take it home with you. Parents never had to decide whether or not the boyfriend should be allowed to stay - they were never asked.

Now, according to Rita O'Reilly of support group Parentline, she and her colleagues get many anxious calls from parents who have been asked that very question. They can't seem to settle on an answer that reconciles their own values, concern for their children's welfare and the desire to be modern parents.

According to Rita, there are two distinct trends emerging.

"Parents of teenagers are being asked if boyfriends and girlfriends can stay the night. They have to bear in mind that at 16 their children are legally entitled to have sex. They can't realistically stop them from having sex after 16, if that's what they want. However, parents have a right to say no to certain activities taking place in their homes. They have to make the rules of the household clear regardless of the teenager's reaction."

This should not become a discussion about the moral implications of sex outside marriage. It is simply a question of house rules and what parents are comfortable with.

Where parents are okay with the idea in principle, says O'Reilly, they should examine issues relating to contraception, the appropriateness of the partner and the potential impact on the rest of the household.

If you agree to the request, make up a bed in the spare room - everyone might be more comfortable pretending that it has been used, even if it hasn't.

The second trend that Rita has noted is a rise in calls from parents of adult children who, because they cannot afford to get a place of their own, are insisting on bringing their partners to stay in the family home. These adults have often travelled or spent time living independently, and they expect to continue in that vein when they return to their parents' house.

According to O'Reilly, the rules are no different just because your child is older. "This is not a matter of right and wrong. It's about what you are prepared to tolerate in your own house."

Depending on your own values, you may be grateful that your son or daughter feels free enough to ask, and view the development as an opportunity to discuss responsible sexual behaviour. However, you shouldn't have to creep around your own house feeling mortified, whatever the prevailing norms.

Parenting Trends - What's new in the world of parenting

From January, Irish support helpline Parentline is offering a new course - "Take a Fresh Look at Parenting Teenagers". Based on their experience of dealing with the concerns of Irish parents, Parentline counsellors have created a programme that examines common conflicts between parents and teenagers and new ways of dealing with them.

The course can be delivered on site at venues around the country on request. Parentline can be contacted Monday to Thursday 10 a.m. to 9.30 p.m. and Friday from 10 a.m. to 4.30 p.m. at local call number 1890 927277.