I'd say about 25/75. Feel free to edit this answer.
If you're an identical twin, its very likely. If not, then its just the same odds
If 1 identical twin has it, the odds are higher than regular siblings that the other twin will get it. If 1 fraternal twin has diabetes, the odds are the same as if any of their siblings have it. But no, if one twin has it, that doesn't necessarily mean both do.
There are no odds. It just happens.
The chances of being born a twin is 1/33
1 in 365.242199
The odds of that happening are one in a million
1 in 365
The odds of being born are astronomicaly low the average man shoots around 20 million sperm. 1 in 20million, but no. Think of it in lower depths the odds of your parents meeting and doing the naughty. Your grandparents being born your great great great great x20 grandparents being born/ meeting eachother. The earth being created. Everything we know. It could be 1 in 9999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999 for all we know.
If one is expecting twins and is wanting to know the odds of twins being two girls the probabilities are that one would have about a 25% chance. It is stated that there is a 50% chance of having one of each or a 25% chance of having twin boys.
In a leap year is 1 in 4 odds On 29th February is 1 in 365 + 365 + 365 + 366 = 1 in 1,461 odds
1 in 730