As a man, I have, on several occasions, been freaked out by one or more of these things.
1)Talking about having or naming babies.
Unless you are pregnant or are currently in possession of an unnamed baby there should be no reason to be playing "if we had a baby what would we name it?" game. Second, the concept of a baby is scary to a man because it means they are essentially tied to you forever. If the a guy has not thought about the possibility of being with you forever, which develops over time, then, anything baby-related is scary.
2)Talking about marriage and the future too often.
It's not that men don't want to get married and have a fruitful future, but it's generally not at forefront of of their thinking until much later on in their lives. Some women have been thinking about it since they were in diapers and have their marriage pre-planned out to the very last detail. When they see a guy, they are thinking of how good of a long-term partner he can be and how he looks in this pre-planned, future life they spent years designing. Men are usually thinking of establishing whether or not the women is a psycho or not in the short term. Besides, how one have such a precise plan for something that hasn't happened yet?
3) "Ladies Night."
When the words "LADIES NIGHT" are mentioned it has an ominous ring to it. In a man's mind, it means there is an issue in your relationship and the case is being submitted to a jury of her peers. Any of her friends that don't like you will now have the chance it plant an incendiary device with your name on it in her head. "Ladies Nights" can be especially ominous if a girl doesn't do them often, then after some kind of recent conflict or slump she suddenly goes on one. "Ladies Nights" can often be the precursor to impending doom so avoiding the specific phrase "Ladies Night" is a good idea. Otherwise there is nothing wrong ladies with chilling with their lady friends. In fact, it should be encouraged, because women are willing to discuss so many things men really don't care to talk about.