chances of having all the same gender?

statistics dont matter to your question but the time of conception.

if you have sex a few days before ovulation you have a good chance of having a girl and if you have sex on the day or just after ovulation its more likely going to be a boy.

as male sperm swim faster but dont live as long as female sperm.

so in the first case the girl sperm would be the survivors and waiting for the egg and for a boy they just get there first when the egg is waiting for them.

PS that's based on large numbers of statistics I read, I am not trying to contradict what any individuals have been told by doctor about specific situations.

Not true according to in-gender.com - has a great section with stats and all. Apparently if you keep having boys you are only slightly more likely to keep having them - with girls it's the other way round. But given there are 51% males born and 49% girls, makes sense for it to be slightly skewed. If some men have super-fertile sperm the Ys will live longer and be faster (resulting in a boy). If you believe that stuff.

After 2 girls I was told by my consultant that the odds of having a boy were 50/50 - he cast doubt on the predisposition thing, though I have heard from other (scientific) sources that some women have a ceratin acid/alkaline balance that will 'predispose' the survival of boy over girl sperms (and vice versa). Ie, that while the sperm initially dtermines the sex, the women's body will 'sift out' the male (or female) sperms that are best suited to the balance of the uterus (in terms of acid/alkaline). Hence as TIGGIWINKLE says, it may be that some couples will be predisposed to have babies of a certain. Oh and baby 3 was a girl too . Will be ttc this Spring, so we'll see if dc 4 will be a girl too!

When I was having my 5th baby, (after 4 boys) my consultant told me I was "extremely unlikely" to have a girl. She said as a couple, DH and I were predisposed to have boys-with another partner the odds would have been back to normal apparently.
Number 5 was a boy, by the way!

I'm one of four - two boys followed by two girls. I saw data the other day in the New Scientist (I think) that suggested older men tended to have more girls... seemed to be the case in my family

There's something about males though, if you've already had 2 boys the chance is 55-60% you'll have another boy. I forget why. No idea about girls.

stats: if you have 2 same sex 80pc chance 3rd will be different
if you have 3 same sex 80pc chance 4th will be same
i THINK
someone told me and it stuck in my random fact addicted brain