Twin Zygosity Questionnaire

PHYSICAL DIFFERENCES

1. Are there differences in the shade of your twins' hair?  

         
         None  
         Only slight differences 
         Clear differences 
 

2. Are there differences in the texture of your twins' hair 
(fine or coarse, straight or curly etc.)?

         
         None  
         Only slight differences 
         Clear differences 
 

3. Are there differences in the colour of your twins' eyes?  

         
         None  
         Only slight differences 
         Clear differences 
 

4. Are there differences in the shape of your twins' ear lobes?  

         
         None  
         Only slight differences 
         Clear differences 
 

5. Did the twins' teeth begin to come through at about the same time?

         The twins' teeth have not come through yet 
         Matching teeth on the same side came through within a few days of each other 
         Matching teeth on opposite sides came through within a few days of each other
         Different teeth came through within a few days of each other 
         The twins' first teeth did not come through within a few days of each other 


6. Do you know your twins' ABO blood group and Rhesus (Rh) factors? 

                First born    Second born
Blood Group   
         Don't Know 
         O  
         A 
         B  
         AB  
  
         Don't Know 
         O  
         A 
         B  
         AB  
 
Rhesus Factor 
         Don't Know 
         Positive  
         Negative 
  
         Don't Know 
         Positive  
         Negative 


7. As your twins have grown older, has the likeness between them: 
 
         
         Remained the same  
         Become less 
         Become more  
 


TELLING THE TWINS APART

8. When looking at a new photograph of your twins, can you tell them
apart (without looking at their clothes or using any other clues)?
 
         
         Yes, easily  
         Yes, but it is hard sometimes 
         No, I often confuse them in photographs  
 

Do any of the following people ever mistake the twins for each other?  

9. Other parent of the twins
 
         
         Yes, often  
         Yes, sometimes 
         Rarely or never  
 

10. Older brothers or sisters  
 
         
         Yes, often  
         Yes, sometimes 
         Rarely or never  
	 (no brothers or sisters) 
 

11. Other relatives  
 
         
         Yes, often  
         Yes, sometimes 
         Rarely or never  
 

12. Babysitter / day carer 
 
         
         Yes, often  
         Yes, sometimes 
         Rarely or never  
 

13. Parent's close friends 
 
         
         Yes, often  
         Yes, sometimes 
         Rarely or never  
 

14. Parent's casual friends
 
         
         Yes, often  
         Yes, sometimes 
         Rarely or never  
 

15. People meeting the twins for the first time 
 
         
         Yes, often  
         Yes, sometimes 
         Rarely or never  
 

16. If the twins are ever mistaken for one another, 
does this ever occur when they are together? 

         
         Yes, often  
         Yes, sometimes 
         No, almost never  
         They are not mistaken for one another  
 

17. Would you say that your twins: 

         
         Are as physically alike as "two peas in a pod" (virtually the same)  
         Are as physically alike as brothers and sisters are 
         Do not look very much alike at all