According to Ukrainian culture, a woman should be married and have children; being single is a shame or weird.
Any woman who is unmarried at the age of 22-23 is considered as "old maid".
There may be a big probability that one becomes a complete leader while the other one becomes a totally leaded in relationships with 5 years age difference.
It may be very hard to maintain such relationships, that’s why it is advised to pay a serious attention on these matters.
One can suspect materialistic interests in such relationship, psychologists may diagnose 'Electra complex', though the biologists state that such uni0ns are more than rational and give future children good chances in the meaning of evolutional development.