Two new kittens, new pet owner help?

You get them spayed/neutered. Kittens can be spayed/neutered at wight 2 pounds which is about 8 weeks of age.

Kittens can go into their heat cycles as early as age 4 months so get them fixed before then.

Congratulations on your new family members.

They also need to be dewormed and started on their kitten vaccines if they haven't already started.

The best thing you can do it get them spayed and neutered. Along with not mating doing this will make the kittens healthier. They can also live a longer life. With the male kitten he will be less agressive trying to find a mate and he won't spray on everything when he gets older. Cats can have lots of babies. When they do have babies they usually get dumped on the streets and have even more. Please get these cats spayed and neutered. We don't want even more animals getting killed.

Get both neutered and spayed by 4 months old or keep them separated. Kittens as young as 4 months are capable of breeding.

Spay or neuter by about 4 to 5 months. Eight weeks is too young and can cause health problems later on.

being litter-mates, there shouldn't be too much competition; and yes, 4 months is around the time they can become sexually mature, so spaying/neutering at around 1 kilogram in weight or 3.5 months whichever is the earliest! you'll probably find the female kitten will spray still even after her 'vet visit' but it doesn't smell like an unneutered tom does!

Sit down, relax.

Cat siblings NEVER mate. No, really, never. They know they are related, and they don't produce any offspring.

The problem you might encounter in spring is they'll escape and return three weeks later with a belly full of, well: nice little cute cats from another cat, and mama cat may bring you a surprise of five.

The only way to ensure they do not mate is to spay and neuter them. Cats become sexually mature at 4 months of age, so you don't have a lot of time. My suggestion is to definitely neuter the male first. The main reason for this is that once a male cat reaches sexual maturity it is likely to spray (urinate) to mark his territory and it will smell really bad and the odor is almost impossible to get rid of. If you neuter him later on he will still spray, although it may not smell as bad. Female cats may urinate outside the cat box as well, but the odor is not as bad. However she needs to be spayed to prevent her from going into heat (their behavior can drive you crazy), plus you may have stray males come around your home and spray outside because they smell the female in heat.

The only guaranteed way to make sure they do not mate is to get them both fixed. Cats can mate at a very young age, and it isn't rare that they mate with their siblings. Go to your local vet and have them both looked at and vaccinated. While you are there, you can talk to the vet about the procedure.

get them spayed and neutered, it's the best thing to do with pets anyway, male cats not neutered will start spraying at a certain age, and females if they get out even one time could leave you with an unplanned unwanted litter

Get them both fixed at 5 months.