Women & men have different body clocks
Women are going to bed later than they should and waking up later than they should because their circadian clocks are two hours ahead of mens’ but they feel they have to go to bed at the same time as their husbands or boyfriends (is that really true these days?)
So they are more tired at night but more alert in the morning and may be prone to insomnia (as women are 50% more likely to have sleep problems).
The circadian clock in our bodies regulates sleep-wake cycles and makes us feel alert or tired at appropriate times and is also responsible for jet-lag when we change time zones.
Humans can have different circadian rhythms and research on teenagers has led to some school starting lessons later to match them.